Institute of Solid State Physics Institut für Festkörperphysik 2009

Transcription

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Technische Universität Berlin
Institute of Solid State Physics
Institut für Festkörperphysik
2009 – 2010
Hardenbergstr. 36
D-10623 Berlin
Germany
Phone:
Fax:
E-Mail:
(30) 314-220 01
(30) 314-220 64
[email protected]
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3
Front Cover
InAs/GaAs submonolayer nanostructures
Design: Dr. Sven Rodt, AG Bimberg
Back Cover
Some of the larger projects and agencies funding our work, 2009 - 2010.
Layout: Dipl.-Phys. Philip Wolf, AG Bimberg
Explanation of the Acronyms on the Back Cover:
100 x 100 Optics: “100 Mbit/sec for 100 Million Users”
is a project of the “Fund for Future Development of the State of Berlin”
VISIT: “Vertically Integrated Systems for Information Transfer”
is an EU FP7 STREP
PolarCon: “Polarization Field Control in Nitride Light Emitters"
Transregional Research Group funded by the German Research Foundation (DFG)
RAINBOW: "High quality material and intrinsic properties of InN and indium rich nitride
Alloys" is an EU Marie Curie Initial Training Network (ITN)
AGeNT: “Arbeitsgemeinschaft der Nanotechnologie-Kompetenzzentren Deutschlands”
The “Association of the Nanotechnology Centers of Competence in Germany”
is funded by the Federal Ministry for Education and Research (BMBF)
Berlin WideBaSe: “III Nitrides Wide Bandgap Semiconductors”
is an innovative regional growth core, funded by the German Federal Ministry for Education
and Research (BMBF)
SFB 787: “Semiconductor NanoPhotonics”
is the Collaborative Research Center 787 of German Research Foundation (DFG)
FEMTOBLUE “Blue Femtosecond Laser Implemented with Group-III Nitrides”
is an EU 7th FWP (Seventh Framework Programme) project
NATO: „ Electrically driven Quantum Dot single Photon Sources for Data Encryption “
is a joint project funded by the NATO Science for Peace and Security Programme
HiTrans: „Grundlagen für hochbitratige Transceiver für Optical Interconnect Anwendungen“
is a joint project within the ProFIT-programme funded by the State of Berlin
QD2D: „Coupling of Single Quantum Dots to Two-Dimensional Systems
is a NanoSci ERA-project funded by the EU-FP 7 - Marie Curie-Work Programme and DFG
SANDiE: „ Self-Assembled Semiconductor Nanostructures for new Devices in Photonics and
Electronics “ is a Network of Excellence-project of the EU -FP 6 - Nano Material Programme
(NMP)
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CONTENTS
1. PREFACE
7
2. PRIZES AND AWARDS
11
3. DISSERTATIONS
13
STRUCTURE AND STAFF OF THE INSTITUTE
21
4. 4.1 4.2 4.3 4.4 4.5 4.6 4.7 5. Office of the Executive Director (01.01.2010)
Departments of the Institute
Workshops
Center of NanoPhotonics
Affiliated Scientific Units
External and Retired Faculty Members of the Institute
Honorary, Adjunct and Guest Professors, Humboldt Awardees and Fellows
21 21 21 22 23 27 27
FOREIGN GUESTS
29
PARTICIPATION IN COMMITEES
33
6. 6.1 6.2 7. Program and Advisory Committee
Editorial Duties / Boards of Institutes and Companies
33 35
TEACHING
37
PATENTS
39
SCIENTIFIC ACTIVITIES
41
8. 9. 9.1 Department I
Prof. Dr. phil. nat. Dieter Bimberg
9.1.1 Staff
9.1.2 Summary of Activities
9.1.3 Publications
9.1.4 Invited Talks
9.1.5 Diploma Theses
41 41 44 51 63 66 5
9.2. Department II
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9.2.a Department IIa
Prof. Dr. rer. nat. Christian Thomsen
9.2a.1 Staff
9.2a.2 Summary of Activities
9.2a.3 Publications
9.2a.4 Invited Talks
9.2a.5 Diploma Theses
67 67 69 70 73 75
9.2.b Department IIb
Prof. Dr. rer. nat. Janina Maultzsch
9.2b.1 Staff
9.2b.2 Summary of Activities
9.2b.3 Publications
9.2b.4 Invited Talks
77 77 77 79 80
9.2.c Department IIc
Prof. Dr. Axel Hoffmann
Prof. em. Dr.-Ing. Dr. h.c. mult. Immanuel Broser
9.2c.1 Staff
9.2c.2 Summary of Activities
9.2c.3 Publications
9.2c.4 Invited Talks
9.2b.5 Diploma Theses
81 81 82 84 89 90
9.3 Department III
Prof. Dr. rer. nat. Mario Dähne
Prof. em. Dr.-Ing. Hans-Eckhart Gumlich
9.3.1 Staff
9.3.3 Publications
9.3.4 Invited Talks
91 91 92 96 98 100
9.4 Department IV
Prof. Dr. rer. nat. Michael Kneissl
Prof. Dr. rer. nat. Wolfgang Richter (retired)
9.4.1 Staff
9.4.3 Books
9.4.4 Publications
9.4.5 Invited Talks
9.4.6 Diploma, Master-, and Bachelor Theses
101 101 103 108 108 113 116 6
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1.
PREFACE
The Institute of Solid State Physics presents its eleventh biannual progress report in an
advanced lay-out. Founded in 1974 the Institute is located since 1985 in the Eugene Paul
Wigner Building at Hardenbergstraße, next to the center of Berlin. There it disposes of
spacious lecture halls, seminar rooms and state-of-the-art laboratories. Our scientific work is
focussed on epitaxial growth of compound semiconductor hetero- and nanostructures,
research on novel materials like carbon nanotubes, physics of semiconductor and carbon
nanostructures, as well as physics and technology of nano-photonic and –electronic devices
and
systems.
Development
of
nanoscopic
measurement
techniques,
like
cathodoluminescence, cross-section scanning tunneling microscopy, near field scanning
optical microscopy, microphoto-luminescence, and micro-Raman are essential and common
basis of the research activities of our four scientific departments.
In the “Center of NanoPhotonics” CNP, affiliated to the institute, novel devices like Single
and Entangled Photon Emitters,
high bit rate and energy efficient Vertical
Surface Emitting Lasers, QD high speed Edge Emitters and Semiconductor Optical
Amplifiers, high power Photonic Band Crystal Lasers, Nanoflash memories,
ultraviolet
LEDs, GaN-based external cavity surface emitting lasers, and high power blue and green laser
diodes… are developed, based on a multitude of often complex heterostructures. Most
modern education and research on devices and their technology are offered here to our
students and PhD candidates. In addition, the CNP provides assistance to small and medium
size companies and has acted in the last 2 years as incubator for three start-ups: VI Systems in
Berlin, PBC Lasers in Berlin, and Azzurro Semiconductors in Magdeburg.
The Berlin government agreed to the joint proposal of our faculty and the president for the
creation of both, a new chair on “Quantum Devices” and an additional Junior Professorship
on “Optoelectronic Devices” at the institute. Both positions are expected to be filled in the
first half of 2011.
The success of the institute and the large number of students, PhD candidates and postdocs it
employs, depends now since more than a decade mostly on external financial resources. The
funding from TUB and our state government in Berlin covers less than 20 % of cost of
consumables and equipment. The most important funding agency continues to be the German
Research Foundation (DFG). The Collaborative Research Center (CRC) “Semiconductor
Nanophotonics” (Sfb 787), and its Integrated Research Training Group are located at the
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institute. The CRC is funded since January 1st, 2008 for four years, and showed an excellent
start. Cooperation on nanostructure and photonic device research with colleagues from five
other institutions in Berlin (Humboldt University, Ferdinand-Braun-Institute, Heinrich-HertzInstitute, Weierstraß-Institute, Konrad-Zuse-Center) and the University of Magdeburg
presents the basis of the CRC 787. In summer 2011 the CRC hopes for getting a
recommendation by its reviewers towards a prolongation until end of 2015. In addition, single
projects focussing e.g., on collaboration with Russia, on Nanomemories, on GaN-based
Semiconductor Disk Lasers, and the electronic structure of InGaN surfaces were funded by
DFG. We are also participating in the transregional DFG research group 957 (PolarCon) in
which laser and light emitting devices on semipolar GaN surfaces are investigated at TU
Berlin.
Complementary and very important funding came from the government of the State of Berlin
in the framework of its “Zukunftsfonds” and ProFIT Programs. 100 x 100 Optics, HiTrans,…
are some of the projects. The European Union within its FP 7 Program and the NATO
Program “Science for Peace” funded the programs VISIT, QD 2D, PROPHET, FemtoBlue,
RAINBOW, and Cyber Security, respectively. Half of these programs are also coordinated by
TUB.
The national competence center CC NanOp (Nano-Optoelectronics), established already in
October 1998, presented again a very effective and successful means for initiating important
national and European programs on nanodevices. Many of these projects emerged from small
scale projects, so called “Machbarkeitsstudien”, financed by the Federal Ministry of
Education and Research (BMBF) via NanOp. TUB therefore decided to continue its support
of CC NanOp until end of 2011. Based on this decision, the BMBF decided to entrust TUB
with the coordination of all National Centers of Competence in Nanotechnology within a new
body called AGeNT, presently also funded until end of 2011.
The European Union Center of Excellence “SANDiE” in the field of semiconductor
nanostructures, which was cofounded by us, received a continuation of its operation in a
second phase until 2012. Strong links to leading international optoelectronic and
communication companies like Aixtron, INTEL, Jenoptik, Oclaro, OSRAM Opto
Semiconductors, and Sentech have been established within the framework of this program.
We congratulate to the bestowal of an Alexander von Humboldt Award to Professor ShunLien Chuang from University of Illinois at Urbana - Champaign, who joined us beginning of
2009, developing with his host a very successful program on novel “metal clad (some times
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called “plasmonic”) surface emitting lasers”. Professor Gadi Eisenstein, Technion Haifa,
Humboldt Awardee 2006/7 continues to be in Berlin part of each year and supports
enormously our work on high sped devices. We are every grateful to him. Dr. Chongyan Liu
from Nanyang Technological University in Singapore and Dr. Abdul Kadir from the Tata
Institute for Fundamental Research in Mumbai received Alexander von Humboldt
Fellowships in 2009 and are both presently working here.
Prof. Janina Maultzsch received in 2009 a particularly well funded and highly competitive EU
Junior Researcher Starting Grant. We are very proud on her.
A particularly important new development of the last two years was that a number of
postdoctoral scientists and Ph.D. candidates have joined us with full financial support of their
home governments based on the excellent research conducted by the institute.
We are very grateful to all our sponsors, their administrators and cooperating industry for
their continuous help and encouragement.
In order to protect our intellectual property better than in the past and to have a better basis for
cooperation with the industry, we filed and obtained an appreciable number of patents. The
support by our local patent agency IPAL proved here to be of outmost importance.
The scientific part of the present report will certainly provide sufficient evidence that the
funding we received carried excellent results. Particular appreciation of our scientific
achievements was expressed by the bestowal of a number of awards to students and postdocs
listed in part 2 of the report.
Physics is a science not bound to a country or to borders. This ”discovery” led to an
increasing number of our students and scientists in the past to pursue their research for longer
time like a year at foreign universities in Tokyo, Los Angeles, Glasgow, Texas, Berkeley, …
to mention only a few. We would like to thank particularly their local hosts. We will further
encourage our co-workers to combine the challenges of different cultures and languages with
achievements in their scientific work.
Scientific contacts with further institutions at many different locations in Europe, Japan or
USA continued to flourish. Especially strong collaborations including short time exchange of
scientists developed or continued to research institutions and universities in Beijing,
Cambridge, Cork, Göteborg, Novosibirsk, South Carolina, St. Petersburg, Taipei,… to
mention only a few.
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Additional and particularly large burdens were taken over by all of the faculty staff of the
institute in order to serve TUB and the scientific community as members or chairmen of
committees on the local, national and international scale, e.g., within advisory or program
committees.
The reelection of Prof. Christian Thomsen as Dean of the Faculty of Mathematics and Science
in spring 2009 and his devotion for developing multimedia eLearning and eResearch should
be particularly mentioned here.
Finally, the enthusiasm and the dedication of all of our collaborators at the institute should be
honoured, being fundamental to our success. The key element for future progress of the
institute continues to be their motivation to generate new ideas and to work hard.
This report will
-
give an overview of the formal structure of the institute and list staff and students
-
summarize our teaching activities in order to provide information on our involvement in
the education of young students and scientists
-
summarize the scientific activities of our research groups, including lists of the
approximately 200 scientific papers we published or which have been accepted for
publication within the past 24 months.
Dieter Bimberg
Executive Director
March 2011
Postscriptum
After having served as excecutive director of the institute for more than two decades,
initiating a complete restructuring of its research directions, creating state-of-the-art MOCVD
laboratories and the Center of NanoPhotonics amongst many other things I retired from this
position in April 2011. I wish my successor, Michael Kneissl, all the success he will need to
guide the institute through the next years.
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2.
PRIZES AND AWARDS
Prof. Dr. Dieter Bimberg
William-Streifer Scientific Achievement Award
as “Pioneer of Semiconductor Nanophotonics”
IEEE Society, Denver, Colorado, USA, November 2010
Dipl.-Phys. Gordon Callsen
Physik-Studienpreis 2010 der Wilhelm und Else HeraeusStiftung
Magnus-Haus Berlin, Germany, Juli 2010
Dipl.-Phys. Gerrit Fiol
Chorafas-Prize 2009 for his investigation of the
“Quantum Dot Lasers for Short Pulse Generation“
Dimitri N. Chorafas Foundation,
Luzern, Switzerland, July 2009
Dipl.-Phys. Tim Germann
CHORAFAS-Prize of the year 2010 for his investigation
of “Quantum Dot Semiconductor Disk-Lasers “
Dimitri N. Chorafas Foundation,
Luzern, Switzerland, August 2010
Dr. Lena Ivanova
Best Poster Award
International Nano-Optoelectronic Workshop (iNOW)
Stockholm, Sweden, and Berlin, Germany, August 2009
Dr. Lena Ivanova
SKM-Dissertationspreis,
Sektion Kondensierte Materie (SKM) der Deutschen
Physikalischen Gesellschaft (DPG)
Regensburg, Germany, March 2010
Dipl.-Phys. Raimund Kremzow
Best Poster Award (1st Prize)
M.Sc.-Phys. Neysha Lobo
Honorable Mention Best Poster Award
Dr. Andreas Marent
Nanowissenschaftspreis 2010 by AGeNT-D
(second place) together with Dr. Martin P. Geller
Prof. Dr. Janina Maultzsch
ERC Starting Independent Researcher Grant 2010
European Research Council, ERC, July 2010
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Dr. Alex Mutig
SANDiE-PhD-Preis 2010
SANDiE-Network of Excellence,
September 2010, Valencia, Spain
Dr. Alex Mutig
Springer PhD-Prize
for his thesis “High Speed VCSELs for Optical
Interconnects” in the book series Springer Thesis,
Heidelberg, January 2011
Dipl.-Phys. Erik Stock
1st place in Section 1: Nanoelectronics, Nanophotonics,
Nanomaterials for Electronics, Magnetic Systems, and
Optics, Photovoltaics for his paper:
”GHz Electrically driven microcavity single photon
source”
Second International Competition of Scientific Papers in
Nanotechnology for Young Researchers at Rusnanotech
2009, Moscow, Russia, October 2009
Dr. Hagen Telg
Carl-Ramsauer Prize 2010 for his excellent dissertation,
Berlin, Germany, November 2010
Dr. Tim Wernicke
Honorable Mention Best Poster Award, iNOWInternational Nano-Optoelectronic Workshop (iNOW)
Dr. Tim Wernicke
Chorafas Prize for his dissertation on “Growth of non-and
semipolar InAlGaN heterostructures for high efficiency
light emitters”, Berlin, Germany, October 2010
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3.
DISSERTATIONS
Department I
Dr. Till Warming
Elektronische Struktur angeregter Zustände einzelner
InAs-Quantenpunkte
Electronic structure of excited states of single InAs quantum
dots
20.02.2009
Photo
excitation
spectroscopy
and
resonant
photoluminescence spectroscopy were combined to
unambiguously identify the main excitation and
recombination channels of single quantum dots, as well as the
corresponding energy levels. By comparison with theoretical
results, the impact of exchange interaction and the resulting
fine-structure splitting can be deduced – one of the key
parameters for single-QD devices.
Thesis reviewers: D. Bimberg, A. Hoffmann (TUB) and
J. Christen (Otto-von-Guericke University, Magdeburg)
Dr. Konstantin Pötschke
Untersuchungen zur Bildung von Quantenpunkten im
Stranski-Krastanow und im Submonolagen Wachstumsmodus
Formation of quantum dots in Stranski-Krastanow and
Submonolayer growth mode
27.02.2009
In this work, Konstantin Pötschke extended the understanding
of the formation of InAs quantum dots in the StranskiKrastanow growth mode. For the first time, the influence of
all main growth parameters on the luminescence properties of
InAs/GaAs nanostructures, grown in the submonolayer
growth mode, was studied comprehensively and
systematically, and the electronic and optical properties of
these structures were discussed.
Thesis reviewers: D. Bimberg and A. Krost (Otto-vonGuericke University, Magdeburg)
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Dr. Anatol Lochmann
Entwicklung und Untersuchung quantenpunktbasierter
Einzelphotonenquellen
Development and investigation of quantum dot based single
photon sources
30.04.2010
This thesis presents the development and implementation of
various novel and patented concepts of single photon sources.
The first approach for single photon sources based on
electrically-driven QDs is the use of a micron-size aluminumoxide aperture.
In this device, only one electron and one hole at a time tunnel
into one QD. The next step was the development of a
Resonant Cavity LED-type (RCLED) single photon source in
order to increase the output coupling efficiency and the QD
emission rate.
Furthermore, detailed numerical device modeling was
performed, in order to do a systematic optimization process of
the device design.
As the result, the presently fastest electrically pumped,
quantum dot based single photon sources could be realized.
Thesis reviewers: D. Bimberg and A. Hoffmann (TUB)
Dr. Thorsten Kettler
Halbleiterlaser hoher Brillanz
High Brightness Semiconductor Lasers
04.05.2010
In his dissertation Thorsten Kettler studied photonic-bandcrystal (PBC) lasers, a new approach to obtain high output
powers with extremely low vertical far-field divergence,
excellent beam quality and therewith a high brightness of the
emitted beam. PBC lasers have a broad waveguide in vertical
direction, composed of alternating layers with different
refractive index. These layers build a one-dimensional
photonic crystal, discriminating higher-order modes so that
single-mode emission can be reached in spite of the large
near-field dimension. Thorsten processed and characterized
single lasers as well as laser arrays built of optically coupled
and uncoupled emitters. These lasers showed vertical far-field
divergences down to 6°, single-mode lasers demonstrated
output powers up to 3.5 W.
Thesis reviewers: D. Bimberg and M. Weyers (FerdinandBraun-Institut, Berlin)
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Dr. Alex Mutig
Oberflächenemittierende Quantenpunktlaser
High-speed VCSELs for optical interconnects
15.07.2010
In his doctorate Alex Mutig focused on the research of highspeed 850 nm and 980 nm vertical-cavity surface-emitting
lasers (VCSEL). He was able to achieve highly recognized
world-record performance like data rates up to 40 Gbit/s or
highly temperature-stable devices. His research included all
aspects from device design, manufacturing in a class 10 cleanroom, high-speed characterization to thorough data analysis.
His thesis was awarded with the Springer Prize and published
as a book within the series “Springer Theses: Recognizing
Outstanding PhD Research”.
Thesis reviewers: D. Bimberg and S.L. Chuang (University of
Illinois, USA)
Dr. Andreas Marent
Entwicklung
einer
neuartigen
QuantenpunktSpeicherzelle
Development of a novel quantum dot memory cell
22.10.2010
In this work the charge carrier dynamics in quantum dot based
memory structures has been investigated experimentally as
well as theoretically and prototypes of a novel memory
concept have been implemented.
The work is divided in two parts:
1. Development and application of measurement techniques
and simulation methods to investigate the memory operations
(storage, writing and erasing) in quantum dot based memory
structures.
2. Development of quantum dot based memory concepts
which fulfill the prerequisites of the ultimate memory (storage
time > 10 years and write time < 10 ns) and the
implementation of these concepts by prototypes.
Thesis reviewers: D. Bimberg and J. Christen (Otto-vonGuericke University, Magdeburg)
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Dr. Erik Stock
Self-organized quantum dots for single photon sources
03.12.2010
In his thesis Erik Stock studied self organized quantum dots
for their application as sources for single photons and
entangled photon pairs.
Prototypes of electrically pumped single photon devices could
be driven with a pumping rate of up to 1 GHz, still
demonstrating
non-classical
light
emission.
The
characterization of quantum dots grown on (111) GaAs
substrates showed a strongly reduced fine-structure splitting
in comparison to (001) grown QDs, making these new
quantum dots a promising candidate for the generation of
entangled photons. The first observation of a LO-phonon
replica from a single InGaAs QD demonstrates the influence
of the wavefunction on the phonon coupling.
Thesis reviewers: D. Bimberg and V. Gaysler (Institute of
Semiconductor Phyiscs, Novosibirsk, Russian Federation)
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Department II
Dr. Holger Lange
Optical phonons in colloidal CdSe nanorods
05.11.2009
Dr. Hagen Telg
Raman studies on individual nanotubes and nanotube
ensembles – vibrational properties and scattering
efficiencies
06.11.2009
Dr. Stephan Brunken
Metallsulfid-unterstützte Kristallisation von stark (001)texturierten Wolframsulfidschichten
25.11.2009
Dr. Thomas König
Investigation of Defects on MgO Films grown on Ag(001)Combined Dynamic Force and Scanning Tunneling
Microscopy Study
01.07.2010
Dr. Marcel Mohr
Electronic and Vibrational Properties of Carbon and
CdSe nanostructures
23.07.2010
Dr. Dirk Heinrich
Strukturbildung in Ferrofluiden unter Einfluss
magnetischer Felder
02.09.2010
Dr- Matthias Müller
Electronic properties of functionalized carbon nanotubes
08.12.2010
Dr. Munise Cobet
Ellipsometric Study of ZnO from multimode formation of
exciton-polartons tot he core-level regime
12.07.2010
Dr. Markus R. Wagner
Fundamentel properties of excitons and phonons in ZnO:
A spectroscopic study oft he dynamics, polarity, and
effects of external fields
09.12.2010
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Department III
Dr. Kai Hodeck
Development of a scanning nearfield optical microscope
for low-temperature investigations of semiconductor
nanostructures
19.02.2009
Using a home-built scanning nearfield optical microscope
(SNOM), the photoluminescence of single quantum dots was
investigated under varying excitation intensity at different
temperatures between 5 K and 300 K. The homogeneous
thermal line broadening was studied in detail, and the binding
energies of exciton complexes such as biexcitons and trions
could be determined.
Dr. Lena Ivanova
Nitrogen containing III-V semiconductor surfaces and
nanostructures studied by scanning tunneling microscopy
and spectroscopy
01.09.2009
Using cross-sectional scanning tunnelling microscopy
(XSTM) and spectroscopy (XSTS), different nitrogen
containing III-V semiconductor surfaces and nanostructures
were studied. In diluted GaAsN single nitrogen atoms could
be identified, a splitting of the GaAs conduction band could
be observed in the density of states, and nitrogen-containing
InAs quantum dots were found to be strongly dissolved. In
atomically-resolved experiments at the GaN(1100) cleavage
surface the intrinsic surface states were found to be outside
the fundamental band gap, different dislocation types could
be characterized in detail, and doping modulation effects
could be detected.
Dr. Jan Grabowski
On the evolution of InAs thin films grown by molecular
beam epitaxy on the GaAs(001) surface
14.12.2010
Thin InAs films were grown on GaAs(001) by molecular
beam epitaxy and studied by in-situ scanning tunnelling
microscopy (STM). A three-step evolution of the InAs
wetting layer was found, starting with In agglomerations on
the GaAs surface, followed by the formation of a (4×3)
reconstructed In2/3Ga1/3As monolayer, on which a (2×4)
reconstructed InAs monolayer was grown. Afterwards the
formation of InAs quantum dots occurred and the critical
thickness could be determined to 1.42 InAs monolayers.
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Department IV
Theodor Herrmann
Optische
Spektroskopie
ferromagnetischen Filmen
an
Metallen
und
02.11.2009
Metal surfaces show superstructures that can be detected via
electron diffraction or optical anisotropy. Optical anisotropies
can be also caused by applying a magnetic field in certain
geometries (MOKE: magneto-optical Kerr effect). To
separate the surface anisotropies from the MOKE signals,
knowledge of the clean and covered surfaces is required.
.
Marc Gluba
Atomare
und
elektronische
Struktur
von
Akzeptorkomplexen und Oberflächen des Zinkoxids
06.07.2010
ZnO semiconductors exhibit a strong background n-type
conductivity. Therefore, the p-doping of ZnO poses great
difficulties. Different causes for the inability to achieve
reproducible p-type doping in ZnO were investigated,
particularly the formation of intrinsic point defects,
compensation, and the formation of molecular nitrogen.
Tim Wernicke
Wachstum von nicht- und semipolaren InAlGaNHeterostrukturen für hocheffiziente Lichtemitter
15.07.2010
Non- and semipolar nitrides do not exhibit the polarization
fields across quantum wells that reduce oscillator strength
and peak gain as in conventional polar nitride devices.
Different concepts for heteroepitaxial and homoepitaxial
growth of non- and semipolar GaN were compared. Bulk
GaN substrates exhibit the best properties and were used to
demonstrate nonpolar current injection LEDs and violet and
blue optically pumped non- and semipolar laser structures
with low thresholds.
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Raimund Kremzow
In situ Rastertunnelmikroskopie an V-III-Halbleiternanostrukturen während der Metallorganischen Gasphasenepitaxie
22.10.2010
A scanning tunneling microscope (STM) was attached to a
metal-organic vapor phase system, to follow the development
of the surface topography with atomic resolution. During the
work the setup was extended by a spectroscopic ellipsometer.
Using this setup the first ever study of Ostwald ripening of
InAs quantum dot in MOVPE was performed.
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4.
STRUCTURE AND STAFF OF THE INSTITUTE
4.1
Office of the Executive Director (01.01.2010)
Prof. Dr. phil. nat. Dieter Bimberg (executive director)
Prof. Dr. rer. nat. Christian Thomsen (deputy executive director)
Prof. Dr. rer. nat. Mario Dähne (deputy executive director)
Prof. Dr. rer. nat. Michael Kneissl (deputy executive director)
Prof. Dr. rer. nat. Axel Hoffmann (chief operating officer)
Ines Rudolph (administrative assistant)
4.2
Departments of the Institute
Department I:
Department IIa:
Department IIb:
Department IIc:
Department III:
Department IV:
Prof. Dr. rer. nat. Wolfgang Richter (retired since 01.04.2005)
4.3
Workshops
Chief operating officer
Mechanical workshop
Werner Kaczmarek (head)
Rainer Noethen
Wolfgang Pieper
Daniela Beiße
Marco Haupt
Electronic workshop
Norbert Lindner
Glasstechnical workshop
Norbert Zielinski
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4.4
Center of NanoPhotonics
Executive director
Prof. Dr. Udo W. Pohl
Chief technology officers
Dr. André Strittmatter (Epitaxy, Department I)
Dr. Werner Hofmann (Processing, Department I)
Technical staff
Ilona Gründler (Department I, until November 2010)
Dipl.-Krist. Kathrin Schatke (Department I)
Dipl.-Ing. Bernhard Tierock (Department I)
The Center of Nano-Photonics provides support to the institute departments by growth,
processing, and analysis of materials and structures. Growth facilities are based on metalorganic vapor phase epitaxy (MOCVD), and processing facilities include dry etching, plasma
deposition, and optical lithography. A second-generation furnace for the selective oxidation of
AlAs to AlOx was developed, enabling precise control in the fabrication of current apertures
in vertical emitters like VCSELs and single-photon emitters.
For two novel kinds of vertical-cavity surface-emitting lasers a proof-of-concept was successfully demonstrated: VCSELs with a monolithically integrated electro-optical modulator
(EOM VCSELs), and microlasers with a metal-coated cavity. EOM VCSELs with precisely
tuned cavities comprising up to 400 layers were grown using MOCVD, and processed to
three-terminal devices. The first EOM VCSELs proved a promising dominant fraction of the
modulation originating from the EO effect, a low power consumption, and open-eye operation
in data transmission at 10 Gb/s. The second type of device aims at the development of nanolasers. Lateral coating of vertical emitting pillar structures by metal allows for realizing very
small modal volume, albeit accompanied by the introduction of optical losses. High-gain
structures comprising optical feedback were grown using MOCVD and processed to flip-chip
microlasers in cooperation with the University of Illinois. For the first time CW-lasing of such
metal-coated devices at room temperature was accomplished. Output power in the µW range
was achieved with devices of 2 µm diameter.
The new oxidation facility enabled a processing scheme with submicron oxide apertures for
efficient single-photon sources with a resonant-cavity. Single-photon emission could be
proved for pulsed devices with 1 GHz repitition rate. The improved oxidation control is also
employed for implementing novel VCSEL designs with reduced parasitics and bandwith well
above 20 GHz.
23
4.5
Affiliated Scientific Units
Collaborative Research Centre (Sfb 787) of the National Science Foundation DFG
“Semiconductor Nanophotonics: Materials, Models, Devices”
Chairman
Prof. Dr. Michael Kneissl, Institute of Solid State Physics, TU Berlin
Vice chairman
Prof. Dr. Dieter Bimberg, Institute of Solid State Physics, TU Berlin
Board of directors
Prof. Dr. Andreas Knorr, Institute for Theoretical Physics, TU Berlin
Prof. Dr. Klaus Petermann, Department of Electrical Engineering, TU Berlin
Prof. Dr. Jürgen Sprekels, Weierstraß Institute for Applied Analysis and Stochastics
Dipl.-Phys. Ronny Kirste
Administrative assistant
Doreen Nitzsche
In 2008 the new Collaborative Research Centre 787 (Sonderforschungsbereich 787)
"Semiconductor Nanophotonics: Materials, Models, Devices" has been established. The
CRC 787 also includes the Integrated Research Training Group “Semiconductor
Nanophotonics” that currently has a membership of more than 65 Ph.D. students with various
scientific backgrounds ranging from mathematics, physics to electrical engineering. Covering
the first four years (2008-2011), the Deutsche Forschungsgemeinschaft (DFG) is supporting
the CRC 787 with more than 11 million Euros. The CRC 787 combines three complementary
research areas: materials, models and devices to develop novel photonic and nanophotonic
devices. In the area of materials, the research activities are focusing on the material systems
GaAs, InP, and GaN which are the most relevant for photonic devices. Thereby the main
objectives are the investigation of new growth mechanisms as well as the fabrication of
integrated nanostructures like quantum wells, quantum dots and sub-monolayer structures.
Based on the development of new materials and the expertise on the physics of nanostructures
we will investigate, fabricate and characterize a number of novel nanophotonic devices. These
include, e.g. the development of electrically driven, quantum-dot based single photon sources
for quantum cryptography, ultra-fast VCSELs for terabit data communication and high
brilliance lasers from the infrared to the green spectral range. Additionally, edge emitter lasers
and amplifiers for the generation and amplification of ultra-short optical pulses at highest
frequencies are being developed. The interdisciplinary character and the strong educational
networking between the different project partners are important features of the Integrated
Research Training Group “Semiconductor Nanophotonics” which features a number of
educational offerings as well as national and international educational activities like the
International Nano-Optoelectronics Workshop iNOW. Another goal of the integrated graduate
school is to encourage the participation of female students in the area nanophotonics and to
support them in their scientific careers. The CRC 787 is comprised of a total of 16 projects
24
from six institutions: The Technische Universität Berlin (Chair University), the HumboldtUniversität zu Berlin, the Otto-von-Guericke-University Magdeburg as well as the FerdinandBraun-Institut, Leibniz-Institut für Höchstfrequenztechnik, the Fraunhofer Institut für
Nachrichtentechnik (Heinrich-Hertz-Institute), the Weierstraß-Institute for Applied Analysis
and Stochastics and the Konrad-Zuse-Zentrum für Informationstechnik.
Photo of the members of the Integrated Research Training Group “Semiconductor Nanophotonics” during the
block seminar in Graal-Müritz 2010.
25
Association of German Nanotechnology Centers of Competence - AGeNT-D:
Arbeitsgemeinschaft der Nanotechnologie-Kompetenzzentren Deutschlands
Chairman
Steering committee
Dr. Andreas Baar (NMN e.V.)
Hr. Alexander Bracht (Hessen NT)
Prof. Harald Fuchs (CeNTech)
Prof. Wolfgang Heckl (Deutsches Museum)
Dr. Regine Hedderich (NanoMat)
Dr. Andreas Leson (UFS)
Prof. Frank Löffler (UPOB e.V.)
Prof. Roland Wiesendanger (INCH)
Prof. Christiane Ziegler (NanoBioNet e.V.)
Dr. Sven Rodt
Doreen Nitzsche
AGeNT-D is the German network of nanotech clusters. It comprises nine competence centres
and two nanotech networks from all over Germany to cover the whole spectrum of
nanotechnology. AGeNT-D promotes R&D, creates synergies and increases national and
international visibility of nanotechnology in Germany.
26
National Competence Center on NanoOptoelectronics of the Federal Ministry of
Education and Research (bmb+f) - NanOp
Chairman
Steering committee
Prof. Alfred Forchel (U Würzburg)
Dr. Norbert Grote (HHI FhG)
Dr. Klaus Schulz (Sodaja Consulting)
Dr. Sven Rodt
Doreen Nitzsche
NanOp is the German national network for the application of lateral nanostructures,
nanoanalytical techniques and optoelectronics. It unites 44 nationally and internationally
leading research and development groups, technical and venture capital companies from
Germany and the A. F. Ioffe Institute from St. Petersburg, Russia.
NanOp has two goals: to speed up research and development in the field of nanotechnologies
for Optoelectronics and to transfer the results to production.
Multimedia Center for eLearning and eResearch (MuLF)
Executive director of the Center
Prof. Dr. rer. nat. Chistian Thomsen
Prof. Dr. rer. nat. Lars Knipping
Staff
Dipl.-Phys. Dirk Heinrich
Sabine Morgner
The Multimedia Center for eLearning and eResearch (MuLF) as a center in our faculty is
responsible for central tasks in the area of information technology-based support of teaching.
Achievements are, e.g., the information system for students (ISIS), the introduction of
electronic chalk, the management system for examinations (MOSES), the electronic eprint
server, or the electronic management system for the "Lange Nacht der Wissenschaften".
Severeal thousand of students across the university are using these services. MuLF advises
newcomers to Eteaching and offers training for the optimal use of the new media at
university. Furthermore, MuLF coordinated the multimedia equipment in the lecture rooms at
the university. Scientifically the center coordinates projects, like, e.g., BeLearning or LiLa,
two European-community funded teaching and research projects[d1].
27
4.6
External and Retired Faculty Members of the Institute
S-Prof. Dr. Norbert Esser, Institute for Analytical Sciences (ISAS) Berlin
apl. Prof. Dr. Rudolf Germer, University of Applied Sciences (FHTW) Berlin
apl. Prof. Dr. Holger Grahn, Paul-Drude-Institute (PDI) Berlin
Priv.-Doz. Dr. Thorsten U. Kampen, Fritz-Haber-Institute (FHI) Berlin
S-Prof. Dr. Bella Lake, Hahn-Meitner-Institute (HZB) Berlin
apl. Prof. Dr. Hans-Joachim Lewerenz, Hahn-Meitner-Institute (HZB) Berlin
apl. Prof. Dr. Michael Meißner, Hahn-Meitner-Institute (HZB) Berlin
apl. Prof. Dr. Norbert Nickel, Hahn-Meitner-Institute (HZB) Berlin
Priv.-Doz. Dr. Harm-Hinrich Rotermund, Fritz-Haber-Institute (FHI) Berlin
Priv.-Doz. Dr. Konrad Siemensmeyer, Hahn-Meitner-Institute (HZB) Berlin
S-Prof. Dr. Michael Steiner, Hahn-Meitner-Institute (HZB), Berlin
S-Prof. Dr. Alan Tennant, Hahn-Meitner-Institute (HZB) Berlin
apl. Prof. Dr. Wolfgang Treimer, University of Applied Sciences (TFH) Berlin
4.7
Honorary, Adjunct and Guest Professors, Humboldt Awardees and Fellows
Department I
Prof. Dr. Shun-Lien Chuang, University of Illinois, Urbana-Champaign, USA,
Humboldt Awardee
Prof. Dr. Gadi Eisenstein, Technion – Israel Institute of Technology, Haifa, Israel,
Humboldt Awardee
Prof. Dr. Hongbo Lan, Shandong University, Jinan, China, Chinese Scholarship
Dr. Chongyang Liu, Agency for Science, Technology and Research (A*STAR), Singapore,
Humboldt Fellow
Department II
Prof. John Robertson, University of Cambridge, United Kingdom,
Humboldt Awardee
Department IV
Dr. Abdul Kadir, Tata Institute of Fundamental Research, Mumbai, India
Humboldt Fellow
28
29
5.
FOREIGN GUESTS
Department I
Ismail Firat Arikan, Istanbul University, Istanbul, Turkey
01.09.2009-28.02.2010
Dr. Sergey Blokhin, A.F. Ioffe Physico-Technical Institute, St. Petersburg, Russia
08.01.-07.02.2009
Jeroen Devreese, University of Antwerp, Belgium
23.01.2009 – 06.02.2009
M.Sc. Wenjuan Fan, Tsinghua University, Beijing, China
11.01.2010-27.01.2010
Prof. Dr. Vladimir Gaysler, Russian Academy of Sciences, Novosibirsk, Russia,
15.03.2009-22.03.2009, 28.11.2009-05.12.2009,
21.04.2010-01.05.2010, 02.10.2010 -05.10.2010
Dr. Nikita Gordeev, A.F. Ioffe Physico-Technical Institute, St. Petersburg, Russia
13.04.2009-25.04.2009
Prof. Dr. Zhibiao Hao, Tsinghua University, Beijing, China
11.01.2010-14.01.2010
Dr. Leonid Karachinsky, A.F. Ioffe Physico-Technical Institute, St. Petersburg, Russia
30.08.2009-14.09.2009
M.Sc. Andrey Krasivichev, Academic Physics and Technology University, St. Petersburg,
Russia, 01.11.2009-15.11.2009, 06.07.2010-02.08.2010
Prof. Dr. Yi Luo, Tsinghua University, Beijing, China
11.01.2010-14.01.2010
M.Sc. Alexey Nadtochy, A.F. Ioffe Physico-Technical Institute, St. Petersburg, Russia
01.03.2009-30.05.2009, 15.03.2010-09.05.2010, 18.10.2010-19.12.2010
Prof. Dr. Nurten Öncan, Istanbul University, Istanbul, Turkey
04.07.2009-12.07.2009
M.Sc. Alexey Payusov, A.F. Ioffe Physico-Technical Institute, St. Petersburg, Russia
30.08.2009-30.11.2009
Dr. Belal Salameh, Tafila Technical University, Tafila, Jordania
14.06.2009-14.08.2009, 06.06.2010-26.08.2010
Dr. Yumian Su, Singapore
01.01.2009-31.12.2010
Dr. Alexander Uskov, Lebebev Physical Institute, Moscow, Russia
01.10.2009-15.12.2009, 16.04.2010-30.06.2010
Türkan Üstun, University of Ankara, Turkey
15.02.2010-31.07.2010
30
Alluri Avinash Varma, Indian Institute of Technology, Kanpur, India
01.10.2009-31.05.2010
Department II
Dr. Konstantin Batrakov, Belarus State University, Minsk, Belarus
01.01.-31.07.2009
Prof. Dr. Nikolaus Dietz, Georgia State University, Atlanta, USA
15.-17.06.2009, 28.05.-04.06.2010
Prof. Dr. Steven Durbin, University of Canterbury, Christchurch, New Zealand
17.-21.03.2010
Dr. Alexander Efros, U.S. Naval Research Laboratory (NRL), Washington, USA,
18.-25.01.2009
Dr. Konstantin Gartsmann, Weizmann Institute of Science, Rehovot, Israel
23.11.-07.12.2010
Dr. Alejandro Goni, Institut de Ciencia de Materials de Barcelona, Spain
05.-20.04.2009, 25.06.-06.07.2009
Franc Güell, Institut de Ciencia de Materials de Barcelona, Spain
01.-05.02.2010
Prof. Dr. Oleg Kibis, State Technical University, Novosibirsk, Russia
01.06.-31.07.2009, 01.06.-31.08.2010
Dr. Jebreel Koshman, Al-Hussein Bin Talal University, Amman, Jordan
26.02.-31.03.2009, 10.06.-10.09.2010
Dr. Polina Kuzhir, Belarusian State University, Minsk, Belarus
01.-30.06.2009
Prof. Dr. Sergey Maksimenko, Belarusian State University, Minsk, Belarus
01.06.-31.07.2009, 01.-31.12.2009, 01.-30.06.2010
Prof. Dr. Bruno K. Meyer, Justus-Liebig-Universität Gießen, Germany
20.-22.02.2009
Prof. Dr. Matthew Philips, University of Technology, Sydney, Australia
12.-17.06.2009, 21.-25.09.2009, 29.06.-04.07.2010
Dr. Anna Rodina, Ioffe Physical Technical Institute, St. Petersburg, Russia
13.-25.01.2009, 10.-23.08.2009, 14.-22.03.2010, 31.07.-28.08.2010
Prof. Dr. Zlatko Sitar, North Carolina State University, Raleigh, USA
10.-13.11.2009
Dr. Gregory Slepyan, Belarusn State University, Minsk, Belarus
01.06.-31.07.2009
Prof. Dr. Tadeusz Suski, Unipress, Warschau, Poland
18.-20.05.2009
31
Dr. Filip Tuomisto, Helsinki University of Technology, Finland
14.-20.01.2009
Jielei Wang, Department of Electronics and Engineering, Georgia State University, Atlanta
USA
16.-31.05.2010
Department III
Frédérick Delgrange, ISEN, Lille, France
Mai-September 2010
Dr. Ph. Ebert, Forschungszentrum Jülich
September 2009, November 2009, April 2010, June 2010, November 2010
Dr. F. Grosse, Paul-Drude-Institut Berlin
September 2010
Prof. Dr. C. K. Shih, University of Texas at Austin, USA
May 2009
Prof. Dr. A. Smith, Ohio University, USA
June 2010
Dr. M. Ternes, Max-Planck-Institut für Festkörperphysik, Stuttgart
February 2009
Dr. R. Timm, Lund University, Sweden
Dezember 2010
Prof. Dr. S. Tsukamoto, Anan National College of Technology, Tokushima, Japan
August 2010
Department IV
Dipl. Phys. Steven Albert, Univ. Polytec. Madrid, Spain
03.-08.10.2010
Dr. Ryan Banal, National Institute of Genetics, Kawakami Laboratory, Kyoto Daigaku,
Japan,
13.-16.06.2009
Prof. Dr. Arnab Bhattacharya, Tata Institute of Fundamental Research, Mumbai, India,
01.-18.06.2009, 24.-30.06.2010
Dr. Sandhya Chandola, The University of Dublin, Trinity College, Dublin, Ireland,
01.01.-31.12.2009
Prof. Dr. Weng Chow, Sandia National Laboratories, Albuquerque, New Mexico, USA,
06.10.-07.11.2009, 26.10.-20.11.2010
Dipl.-Phys. Franscesco Ivaldi, Polish Academy of Science, Warzawa, Poland,
13.- 17.07.2009, 03.- 08.10.2010
32
Dr. Abdul Kadir, Tata Institute of Fundamental Research, Mumbai, India,
24.05.-15.07.2009, 10.09.-31.12.2010
Dr. Slawomir Kret, Polish Academy of Science, Warzawa, Poland
13.-17.07.2009
Dr. Michelle Moram, University of Cambridge, Cambridge, UK
02.-06.06.2009
Prof. Dr. Dimitra Papadimitriou, Institute of Physics, National Technical University of
Athens, Greece
11.-22.02.2009, 03.-28.08.2009, 14.04.-08.05.2010, 04.07.-31.08.2010
Dr. Joachim Piprek, NUSOD Institute LLC, Newark, USA,
08.-14.11.2009, 19.-23.04.2010
Prof. Dr. O. Pulci, Università degli Studi di Roma II ‘Tor Vergata’, Roma, Italy
19.08.-04.09.2010
Dipl. Phys. Linda Riele, Università degli Studi di Roma II ‘Tor Vergata’, Roma, Italy
01.-22.01.2010, 16.08.-21.08.2010, 03.-08.10.2010
Dr. Eugen, Speiser, Università degli Studi di Roma II ‘Tor Vergata’, Roma, Italy
09.-16.02. 2009
Dr. Tomohiro Yamaguchi, National Institute of Genetics, Kawakami Laboratory, Kyoto
Daigaku, Japan
13.-16.06.2009
33
6.
PARTICIPATION IN COMMITEES
6.1
Program and Advisory Committee
Dieter Bimberg
Member of the International Advisory and Program Committee of the “LEOS-Winter Topical
Meeting”, Innsbruck, Austria, January, 12 – 14, 2009
Member of the International Advisory Committee of the “17th International Symposium
Nanostructures: Physics and Technology”, Minsk, Belarus, June 22 – 26, 2009
Member of the International Advisory and Program Committee of the “12th International
Conference on the Formation of Semiconductor Interfaces” (ICFSI-12), Weimar, Germany,
July 5 – 10, 2009
Chair of the Program Committee of the “International Nano-Optoelectronics Workshop”
(iNOW), Stockholm, Swedn, Berlin, Germany, August 2-15, 2009
Chair of the Program Committee of “Nanotech Europe 2009”, Berlin, Germany,
September 28 – 30, 2009
Member of the Program Committee of the “Collaborative Conference on Interacting
Nanostructures” (CCIN), San Diego, CA, USA, November 9 – 13, 2009
Member of the Program Committee of the Symposium “Semiconductor Lasers and Laser
Dynamics Conference” within Photonics Europe, Brussels, Belgium, April 12 – 16, 2010
Member of the International Advisory Committee of the “12th International Ceramics
Congress” (CIMTEC 2010), Montecatini Terme, Italy, June 6 – 11, 2010
Member of the International Advisory Committee of the “18th International Symposium
Nanostructures: Physics and Technology”, St. Petersburg Russian Federation,
June 21 – 26, 2010
Member of the Program Committee of “The 2010 Villa Conference on Interaction among
Nanostructures” (VCIAN-2010). Santorini, Greece, June 21 – 27, 2010
Member of the International Advisory Committee of the “International Conference on
Superlattices, Nanostructures and Nanodevices” (ICSNN-2010), Beijing, China,
July 18 – August 3, 2010
Member of the Program Committee of the “International Nano-Optoelectronics Workshop”
(iNOW), Beijing, China, August 1 – 15, 2010
Axel Hoffmann
Member of the Program Committee of the “SPIE Photonics West”, San Jose, California,
USA, January 2009
Member of Member of the Program Committee of the “Frühjahrstagung der Deutschen
Physikalischen Gesellschaft (DPG)”, Berlin, Germany, March 2009
Chairman of the “E-MRS Spring Meeting 2009” (E-MRS 2009), Strasbourg, France, May 2009
34
Member of the Organization Committee of the Int. Nano-Optoelectronical Workshop
(INOW), Berlin, Germany, July 2009
Member of the Program Committee of the “SPIE Photonics West”, San Francisco, California,
USA, January 2010
Member of the Intern. Advisory Committee, PLMCN X, X. International Conference on
Physics of Light-Matter Coupling in Nanostructures, Cuernavaca, Mexico, February 2010
Member of the Program Committee of the “Frühjahrstagung der Deutschen Physikalischen
Gesellschaft (DPG)”, Berlin, Germany, March 2010
Member of the Advisory Committee of the “8’th International Symposium on Semiconductor
Light Emitting Devices (ISSLED)”, Beijing, China, May 2010
Member of the Program Committee of the “ISGN 3”, Montpellier, France, July 2010
Member of the Advisory Committee of the “International Workshop on Nitride
Semiconductors (IWN)”, Tempa, USA, September 2010
Michael Kneissl
Member of the Program Committee of “Novel In-Plane Semiconductor Lasers VIII”, San
Francisco, USA, January 2009
Member of the local Organizing Committee of the “International Nano-Optoelectronics
Workshop (i-NOW 2009)”, Berlin, August 2009
Member of the Organizing Committee of the E-MRS 2009 Fall Meeting Symposium on ”InN
materials and alloys”, Warsaw, Poland, September 2009
Conference chair of the “DGKK 2009”, Epitaxy Workshop of “The German Association for
Crystal Growth” (DGKK), Berlin, December 2009
Member of the Program Committee of “Novel In-Plane Semiconductor Lasers IX”, San
Francisco, USA, January 2010
Member of the Program Committee of the “International Workshop on Nitride
semiconductors” (IWN 2010), Tampa, Florida, USA, September 2010
Janina Maultzsch
Member of the organizing committee: “Electronic Properties of Novel Materials”, Kirchberg,
Austria, 07.-14.03.2009
Member of the organizing committee: “Electronic Properties of Novel Materials”, Kirchberg,
Austria, 06.-13.03.2010
Markus Pristovsek
Member of the Program Committee of "SemiconNano 2009", Tokushima, Japan, August 2009
Christian Thomsen
Organiser and member of the committee: “Electronic Properties of Novel Materials”,
Kirchberg, Austria, 07.-14.03.2009
Organiser and member of the committee: “Electronic Properties of Novel Materials”,
Kirchberg, Austria, 06.-13.03.2010
35
6.2
Editorial Duties / Boards of Institutes and Companies
Dieter Bimberg
International Editorial Advisory Board "Opto-Electronics Review" (O-ER) Warsaw, Poland
Editorial Board, IET Optoelectronics Journal, U.K.
Editorial Board, “Research Letters in Physics”, USA/Egypt
International Board of Editors, “Semiconductor News”, Pakistan
Assoicate Editor, IEEE Photonics Journal, Fort Collins, Colorado, USA
Chairman Scientific Advisory Board, VI Systems GmbH, Berlin, Germany
Chairman of the Board, PBC Lasers GmbH, Berlin, Germany
Member of the International Advisory Board of “Skolkovo Foundation”
Member of the Board “Technopark Skolkovo Ltd.”
Axel Hoffmann
Editorial Board of “physica status solidi (c)”, WILEY-VCH, Weinheim, Germany
Michael Kneissl
Guest Editor of a special issue on “Nonpolar Nitrides” to be published in Semiconductor
Science & Technology, IOP Publishing
Guest editor for the Proceedings of the “International Workshop on Nitride
semiconductors”´(IWN 2010), Physica Status Solidi, Wiley
Member or the Board of the Zentraleinrichtung Elektronenmikroskopie “ZELMI”
Christian Thomsen
Editor physica status solidi
Editor Solid State Communications
Physica status solidi – Rapid Research Letters
IWEPNM 2009, 23rd International Winterschool on Electronic Properties of Novel Materials:
Molecular Nanostructures
IWEPNM 2010, 24th International Winterschool on Electronic Properties of Novel Materials:
Molecular Nanostructures
36
37
7.
TEACHING
Internal faculty members
Lab Course in Methods of Applied Physics I and II
D. Bimberg
Lab Course in Advanced Experimental Physics
D. Bimberg, M. Dähne, A. Hoffmann, M. Kneissl, J. Maultzsch, C. Thomsen
Applied Physics I + II
D. Bimberg, A. Hoffmann, W. Hofmann, U.W. Pohl, M. Weyers
Seminar on Photonics: Materials, Devices, Systems
D. Bimberg, A. Hoffmann, U.W. Pohl, A. Strittmatter
Selected Topics of Solid State Physics
D. Bimberg, C. Thomsen
Semiconductor Epitaxy
U. W. Pohl
Experimental Physics I, II
M. Dähne
Experimental Physics V – Introduction to Solid State Physics
M. Dähne
Seminar on Surfaces, Interfaces and Nanostructures
M. Dähne, H. Eisele, J. Grabowski, L. Ivanova, A. Lenz
Experimental Methods
M. Dähne (organizator)
Applied Physics I: LEED
H. Eisele
Advanced Lab Course: STM
A. Lenz
Exercises for Experimental Physics V
L. Ivanova, J. Grabowski (2009/10) ; C. Prohl, M. Franz (2010/11)
Further Education: Instrumental Analytic, Course 6
M. Dähne, M. Franz, C. Prohl
Macroscopic Quantum Phenomena in Solid State Physics
A. Hoffmann
Modern Methods of Solid State Physics
A. Hoffmann
Solid State Physics I + II
M. Kneissl, P. Vogt, M. Pristovsek, N. Nickel, H.-J. Lewerenz
Lab course in Solid State Physics I + II
M. Kneissl, P. Vogt
Seminar series “Physics of Semiconductor Interfaces and Heterostructures”
M. Kneissl, P.Vogt, M. Pristovsek
Seminar series “Modern Concepts in Optoelectronics”
M. Kneissl, M. Pristovsek
38
Lab Course in Advanced Experimental Physics
M. Kneissl, D. Bimberg, M. Dähne, C. Thomsen
Group Theory in Solid State Physics
J. Maultzsch
Introduction to Physics for Engineering Students I + II
C. Thomsen
Special Topics in Physics for Engineering Students
C. Thomsen
Special Topics in Carbon Nanotubes and Graphene
C. Thomsen & J. Maultzsch
External faculty members
Ultrasonics and Phonons
R. Germer
Introduction to classical physics for engineers
H. Grahn
Organic Semiconductors: performance, production, applications
T. Kampen
Photonic Processes in nanoscience
H.-J. Lewerenz
Surface Physical Research on Energy Converted Semiconductor Structures
H.-J. Lewerenz
Hydrogen in Solid States
N. Nickel
Neutrons as an Efficient Tool to Investigate Condensed Matter
K. Siemensmeyer, B. Lake
Neutron Scattering I
K. Siemensmeyer, B. Lake
31st Berlin School on Neutron Scattering
A. Tennant, B. Lake
Advanced Magnetism
A. Tennant
Selective Sections of Neutron Scattering
A. Tennant
Introduction to Physics for Engineering Students
C. Thomsen, H. Grahn
Introduction to X-ray- and Neutron Computed Tomography
W. Treimer
39
8.
PATENTS
Speicherzelle und Verfahren zum Speichern von Daten
Memory cell, and the method for storing data
USA Patentanmeldung AZ: 12/518,223 (08.06.2009)
Koreanische Patentanmeldung AZ: 10-2009-7014186 (07.07.2009)
Japanische Patentanmeldung AZ: 2010-512012 (16.04.2010)
Martin Geller, Andreas Marent, Dieter Bimberg
Tuning von VCSEL-Kavitäten und Quantenpunktresonanzen durch extern erzeugte
Verspannung mittels piezoelektrischer Aktuatoren
US Patentanmeldung Nr. 12/891,437 (27.09.2010)
Andrei Schliwa, Erik Stock, Dieter Bimberg
Photonenpaarquelle und Verfahren zu deren Herstellung
Internationale Patentanmeldung Nr. PCT/DE 2009/001025 (20.07.2009)
Erteilung deutsches Patent: Nr. 10 2008 036 400.2-33 (21.01.2010)
Momme Winkelnkemper, Andrei Schliwa, Dieter Bimberg
Method for fabricating large area and highly ordered quantum dot array
USA Patentanmeldung AZ: 12/662,661 (27.04.2010)
Hongbo Lan, Udo W. Pohl, Dieter Bimberg
Speicherzelle auf Basis von Nanostrukturen aus Verbindungshalbleitern
USA Patentanmeldung AZ: US 12/970,744 (16.12.2010)
Andreas Marent, Martin Geller, Dieter Bimberg, Tobias Nowozin
P-Kontakt und Leuchtdiode für den ultravioletten Spektralbereich
PCT/EP2010/060333
Prof. Dr. M. Kneissl, PD Dr. M. Weyers, Dr. Sven Einfeldt, Dr. Hernan Rodriguez
40
41
9.
9.1
SCIENTIFIC ACTIVITIES
Department I
9.1.1 Staff
Secretary
Ulrike Grupe
Technical Staff
Jörg Döhring
Ilona Gründler (until 30.11.2010)
Dipl.-Ing. Bernd Ludwig (until 30.06.2010)
Dipl.-Krist. Kathrin Schatke
Dipl.-Ing. Bernhard Tierock
Permanent Guest Scientists
Prof. Dr. Jürgen Christen
Prof. Dr. Shun-Lien Chuang
Priv.-Doz. Dr. Armin Dadgar
Prof. Dr. Gadi Eisenstein
Prof. Dr. Wolfgang Gehlhoff
Prof. Dr. Alois Krost
Prof. Dr. Nicolai N. Ledentsov
Dr. Vitali A. Shchukin
Principal Scientists
Prof. Dr. Udo W. Pohl
Dr. Werner Hofmann
Dr. André Strittmatter
Senior Scientists
Dr. Vladimir Kalosha
Dr. Thorsten Kettler (until 31.10.2010)
Dr. Anatol Lochmann (until 31.10.2010)
Dr. Andreas Marent
Dr. Alex Mutig (until 31.10.2010)
Dr. Konstantin Pötschke (until 30.09.2009)
Dr. Sven Rodt
Dr. Andrei Schliwa (until 31.08.2010)
Dr. Erik Stock
42
Dr. Till Warming (until 31.12.2009)
Dr. Momme Winkelnkemper (until 31.12.2009)
PhD Candidates
Dipl.-Phys. Dejan Arsenijević
Dipl.-Phys. Gerrit Fiol
Dipl.-Phys. Tim Germann
Dipl.-Phys. Ole Hitzemann
Dipl.-Phys. Gerald Hönig
Dipl.-Phys. Thorsten Kettler (until 04.05.2010)
Dipl.-Phys. Anatol Lochmann (until 30.04.2010)
Dipl.-Phys. Andreas Marent (until 22.10.2010)
Dipl.-Phys. Christian Meuer
Dipl.-Phys. Philip Moser
Dipl.-Phys. Alex Mutig (until 15.07.2010)
Dipl.-Phys. Tobias Nowozin
Dipl.-Phys. Irina Ostapenko
Dipl.-Phys. Kristijan Posilovic
Dipl.-Phys. Konstantin Pötschke (until 27.02.2009)
Dipl.-Phys. Holger Schmeckebier
Dipl.-Phys. Jan-Hindrik Schulze
Dipl.-Phys. Erik Stock (until 03.12.2010)
Dipl.-Phys. Gernot Stracke
Dipl.-Phys. Mirko Stubenrauch
Dipl.-Phys. Waldemar Unrau
Dipl.-Phys. Till Warming (until 20.02.2009)
Diploma Students
Dejan Arsenijević (until 16.02.2009)
Alexander Dreismann
Johannes Gelze (28.07.2009)
Alexander Glacki
Annika Högner (until 22.12.2010)
Gerald Hönig (until16.10.2009)
Gunter Larisch
Gang Lou (until 18.10.2009)
Benjamin Maier (until 22.10.2010)
Murat Öztürk
Holger Schmeckebier (until 19.06.2009)
Daniel Seidlitz (until 15.01.2010)
43
Jan Amaru Töfflinger (until 18.03.2010)
Peter Benedikt Weber (until 03.06.2009)
Philip Wolf (until 08.07.2010)
Master Students
Leo Bonato
Alissa Wiengarten
Martin Winterfeldt
Bachelor Students
Moritz Kleinert (until 14.06.2010)
Luzy Krüger
Peter Schneider
Tristan Visentin (until 07.10.2010)
Martin Winterfeldt (until 02.12.2009)
44
The activities of the department are grouped into five mutually connected research areas with
complementary objectives:
-
Nanostructures: Growth and Physics,
-
Surface Emitters: VCSELs, Single/Entangled Photon Emitters, Silicon Photonics,
-
Edge Emitters: High Frequency Lasers and Amplifiers, High Brightness Lasers,
-
Nanoflash Memories,
-
Magnetic Resonance.
A few of the highlights of the last two years are emphasized in the summary below. For an
exhaustive overview on our activities see the list of publications, which can be easily
retrieved in the internet.
A quantitatively correct theoretical description of the electronic structure of quantum dots,
including exchange and correlation effects to describe the excitonic fine-structure splitting,
on surfaces of varying orientation in arsenides and nitrides, presents a major theoretical
challenge. Using the configuration interaction approach in conjunction with eight-band k·p
theory, including first and second order piezoelectric fields, we predict that the confinement
potential of InAs/GaAs quantum dots grown on (111) planes is not lowered by piezoelectric
effects, in contrast to such quantum dots grown on (001) planes. The piezoelectric fields for
these two configurations are shown in figure 1. Thus the excitonic fine structure splitting
vanishes for InAs QDs grown on GaAs (111)-planes as long as no additional symmetry
lowering effects are present. Micro-PL experiments confirm the predictions.
Figure 1: Piezoelectric potentials for lens-shaped InAs/GaAs quantum dots grown on GaAs(111)B and
GaAs(001) substrates.
Surprisingly the excitonic fine-structure splitting was observed in Micro-PL experiments
on GaN/AlN quantum dots also. Here it reaches huge values of up to 7 meV. The size
dependence of the FSS is found to be inverse to that observed for InAs/GaAs QDs. A
shape/strain anisotropy is revealed as being the origin of the large FSS for small GaN/AlN
QDs.
Thus InAs/GaAs QDs grown on (111) surfaces are identified as ideal sources of entangled
photon pairs. GaN/AlN QDs emitting in the UV might enable the realization of roomtemperature single-q-bit emitters for quantum cryptography and communication.
45
The sensitivities of our µ-photoluminescence excitation (µ-PLE) and µ-photoluminescence
(µPL) spectroscopy set-ups were largely improved, such that by a combination of both
methods for the first time ever the energy distances between single hole levels of single
InGaAs QDs could be experimentally determined. Appreciable heavy-hole light-hole
coupling was found to be decisive to explain the observed nonzero h1-h2-splitting. A number
of trion transitions forbidden in the virtual crystal approximation (VCA) are experimentally
observed. Describing the atomic distribution in a QD by a much more realistic granulated
crystal model (Fig. 2) strict selection rules of the VCA are lifted and the experimental results
are explained.
Figure 2: Representations of an InAs/GaAs QD in the virtual crystal approximation and in the granulated crystal
model.
Break-throughs in devices often happen when creative intelligence and time is invested in the
design of improved or novel device technologies or set-ups for their characterization.
Controlled fabrication of single and multiple oxide apertures is of fundamental importance
for the performance of vertical light emitters, VCSELs and single/entangled photon emitters.
We put into operation at the Center of NanoPhotonics a second generation and largely
improved set-ups for fabricating such oxide apertures, including in-situ control, and
immediately recognized the merits of better process control by a multitude of improved
device parameters.
Characterizing all of the 5000+ surface emitters on a 2 inch wafer is hardly possible, if no
automatic procedure is used. We constructed a fully software controlled device mapper, who
delivers after about 20 hours the essential I-V and I-L characteristics, including derived
quantities like threshold current for all of the devices of a wafer. Thus selection of the “best”
is possible.
High frequencies and bit rates up to elevated temperatures like 85°C and sometimes 120°C
are essential for applications of VCSELs in data communication. Our own work focused on
the two wavelengths, 850 nm and 980 nm, presently competing with each other all over the
world, becoming the dominant one for systems ranging from a few cm to about 100 m. For
850 nm VCSELs we reported record 40 Gbit/s error-free transmission with a bit error rate
(BER) smaller than 10-12 (Fig. 3). Introduction of multimode apertures leads to another
record: 25 Gbit/s error-free transmission at 85°C for 980 nm. Detailed analysis of the
various fundamental physical parameters that limit high bit-rate performance like relaxation
resonance frequency, damping factor, D-factor, K-factor, parasitic cut-off frequency, and
others indicate that further design advances will enable operation at still higher
temperatures and bit rates. 22 Gbit/s operation of long wavelength 1.55 µm VCSELs was
additionally demonstrated in collaboration with the group of Professor Amann from TU
Munich.
46
Figure 3: Bit-error rate measurement for a 850 nm VCSEL at 75 °C.
Based on our design experience of VCSELS we developed a new generation of single-q-bit
emitters on demand based on resonant cavity LEDs using an oxide aperture confining the
current to a single InAs quantum dot. The Purcell-effect enhances the emission intensity,
reduces the exciton lifetime and enables the first experimental demonstration of a modulation
frequency of 1 GHz. Improved high frequency design of the devices (Fig. 4) will lead to still
higher cut-off frequencies.
Figure 4: Schematic view of our new high-frequency design for single-photon emitters.
47
The footprint of a VCSEL is only about 1% of that of edge emitting lasers. Yet it is too large
for future heterogeneous integration of light emitters with silicon ICs, in particular for parallel
optical links operating at bit rates larger than 1 Tbit/s with minimum power consumption. A
radically different design approach for surface emitters is based on metal cavities (see Fig. 5),
occupying a surface area of about 1% of that of a VCSEL. Integrated modeling, growth,
processing and characterization of such devices were pursued together with the group of
Professor S.-L. Chuang from U.I. Urbana, and led to immediate success. For the first time
room-temperature operation of such devices, having a diameter of 2 µm, was achieved
resulting in an output power of close to 8 µW. The devices were flip-chip mounted on Sisubstrates, showing an extremely low thermal impedance. Such devices might present in the
future a cornerstone of Si-photonics.
Figure 5: Schematics of our metal-cavity microlaser. The fabricated device has an active region of multiple (14)
quantum wells sandwiched between a silver metal reflector on p-doped GaAs/AlGaAs layers and an n-doped
DBR (flip-chip bonded upside down on a gold coated silicon substrate). The device is surrounded by silicon
nitride and silver on the sidewalls to form a closed optical microcavity. The GaAs substrate below the
DBR/InGaP (etch stop layer) has been removed, and the physical size is 2.0 µm in diameter and 2.5 µm in total
thickness.
QD-based mode-locked lasers driven under optimized conditions still show pulse widths
being much larger than the Fourier-transform limit given by the Gaussian broadened gain
width of such lasers. A detailed investigation of the chirp showed the broadening to be
essentially caused by a linearly chirped emission, excluding a number of different exotic
explanations found in the literature. We compensated the chirp and obtained 40 GHz pulses of
only 0.7 ps width. By multiplexing finally a pulse comb of 0.7 ps pulses at 160 GHz was
demonstrated (see Fig. 6).
48
Figure 6: Autocorrelation measurement (left) and retrieved pulse comb (right) of the hybrid mode-locked device
demonstrating a pulse comb of 0.7 ps pulses at 160 GHz.
Previous investigations of QD-based semiconductor optical amplifiers (SOAs) showed
saturated linear chip gain of up to 35 dB at 1.3 µm. Many future all-optical networks will be
based on the operation of optical devices at high frequencies in a nonlinear range. Wavelength
conversion presents a particular challenge. We demonstrated for the first time wavelength
conversion by 10 nm up to 80 Gbit/s of return-to-zero (RZ) on-off-keying (OOK) signals
with a BER smaller than 10-9 using a QD SOA in combination with a delay interferometer
(DI). Figure 7 shows the BER measurement and the corresponding converted eye diagram of
a pseudo-random binary sequence (PRBS) 231-1 RZ OOK data signal at 80 Gbit/s
representing successful conversion of 80 Gbit/s OOK data signals.
Fig. 7: (a) Eye diagram of the converted 80 Gbit/s data signal at 1320 nm after the DI showing an extinction ratio
of 9.3 dB. (b) Bit error rate versus received power for 80 Gbit/s RZ-OOK wavelength conversion from 1310 nm
to 1320 nm (FSR: free spectral range).
49
Increasing output power and brightness of edge emitting semiconductor lasers (EELs) to
values far above presently obtained ones is challenging, since known commercial concepts
are not believed to have such potential, and rewarding, since many important scientific and
commercial applications, like scribing or cutting, could be covered by inexpensive and energy
efficient light sources. We have designed, fabricated and measured the performance of two
novel design types of EELs, photonic-band-crystal lasers (PBC) and tilted-wave lasers
(TWL), with unconventional waveguides and lateral arrays thereof. Both concepts are
patented. The PBC structure which contains an embedded higher-order mode filter allows us
to expand the ground mode across the entire waveguide. An almost symmetric far field of 7°
results with more than 2 W cw output power and a M2-value of 1.5. The brightness is 1x108
Wsr-1cm-2, more than one order of magnitude larger than reported, yet. Under pulsed
conditions the brightness and peak power are still four times larger. First modeling results
indicate the potential of coherent coupling of stripes, as shown in figure 8 for three stripes.
Figure 8: PBC laser stripes that show coherent coupling of three stripes for small lateral distances.
The „New Scientist“ hailed results of our nanoflash research program (based on our own
patents) as the potential “holy grail” of future semiconductor nano-memories. 106 years of
hole storage time was extrapolated for GaSb/AlAs QD-memory structures (see Fig. 9) from
our present results of about 2 s presently obtained for InAs/AlGaAs-QD hole memories.
Write-times much below 1 ns are expected, governed by the ultrafast relaxation time of holes,
that are independent of the storage time of the carriers. Six nanoseconds, yet controlled by
device parasitic, are observed.
50
Figure 9: Estimated storage times for different QD systems as a function of localization energy.
EPR activities
Diluted magnetic semiconductors (MS) that exhibit ferromagnetism at room temperature are
essential for the development of semiconductor spintronics. According to theoretical
predictions transition metal (TM)-doped AIIBIVCV2 chalcopyrite and the II-VI semiconductor
ZnO are promising compounds of such applications. The magnetic resonance studies of native
defects and their transition energies, investigations of isolated TM on the two different cation
lattice sites in the ternary compounds, on exchanged coupled pairs as well as the interaction of
TMs with native defects were critically analysed and compared with theoretical predictions.
New results about the incorporation of TMs in ZnO nanowires and colloidal ZnO
nanocrystals (NCs) were obtained. We proved that the TM-doped colloidal ZnO nanocrystals
exhibit a core-shell structure revealed by the relative intensity of the EPR spectra and by the
performed surface modifications. The incorporation of Li on Zn sites in ZnO NCs was
demonstrated by the detection both of the axial and non-axial Li defects. The interest of Li as
dopant in ZnO is based on both its possible ability to act as a p-dopant in ZnO, as well as on
the fact that Li is a major impurity in ZnO growth. Besides, new electrically-detected electron
paramagnetic resonance (EDEPR) and optically-detected magnetic resonance (ODMR) results
of impurity centres in nanostructures inserted in silicon microcavities were received.
51
9.1.3 Publications
a)
Nanostructures: Growth and Physics
1.
Few-particle energies versus geometry and composition of InxGa1-xAs/GaAs selforganized quantum dots
A. Schliwa, M. Winkelnkemper, and D. Bimberg
Physical Review B 79, 075443 (2009)
2.
Hole-hole and electron-hole exchange interactions in single InAs/GaAs quantum
dots
T. Warming, E. Siebert, A. Schliwa, E. Stock, R. Zimmermann, and D. Bimberg
3.
In(Ga)As/GaAs quantum dots grown on a (111) surface as ideal sources of
entangled photon pairs
A. Schliwa, M. Winkelnkemper, A. Lochmann, E. Stock, and D. Bimberg
4.
InGaAs quantum dots coupled to a reservoir of nonequilibrium free carriers
J. Gomis-Bresco, S. Dommers, V.V. Temnov, U. Woggon, J. Martinez-Pastor,
M. Laemmlin, D. Bimberg
IEEE Journal of Quantum Electronics 45 (9), 1121 (2009)
5.
Limits of In(Ga)As/GaAs quantum dot growth
A. Lenz, H. Eisele, R. Timm, L. Ivanova, R.L. Sellin, H.Y. Liu, M. Hopkinson,
U.W. Pohl, D. Bimberg, and M. Dähne
Phys. Stat. Sol. (b) 246, 717 (2009)
6.
Quantenpunkte: Design-Atome in Halbleitern
S. Rodt, D. Bimberg
Welt der Physik 7118 (2009)
7.
Quantenpunkte: Technische Anwendungen der «künstlichen Atome»
S. Rodt, D. Bimberg
Welt der Physik 7122 (2009)
8.
Quantum dots for single- and entangled-photon emitters
D. Bimberg, E. Stock, A. Lochmann, A. Schliwa
IEEE Photonics Journal 1 (1), 57 (2009)
9.
Self-assembled quantum dots with tunable thickness of the wetting layer:
Role of vertical confinement on interlevel spacing
L. Wang, V. Křápek, F. Ding, F. Horton, A. Schliwa, D. Bimberg, A. Rastelli, and
O.G. Schmidt
10.
Spectroscopic access to single-hole energies in InAs/GaAs quantum dots
E. Siebert, T. Warming, A. Schliwa, E. Stock, M. Winkelnkemper, S. Rodt,
and D. Bimberg
52
11.
A tribute to Zhores Ivanovitch Alferov, a pioneer who changed our way of daily
life
D. Bimberg
Semiconductor Science Technology 26, 010301 (2010)
12.
Atomic structure of buried InAs sub-monolayer depositions in GaAs
A. Lenz, H. Eisele, J. Becker, L. Ivanova, E. Lenz, F. Luckert, K. Pötschke,
A. Strittmatter, U.W. Pohl, D. Bimberg, and M. Dähne
Appl. Phys. Express 3, 105602 (2010)
13.
Band parameters and strain effects in ZnO and group-III nitrides
Q. Yan, P. Rinke, M.Winkelnkemper, A Qteish, D. Bimberg , M. Scheffler,
and C.G. Van deWalle
14.
Confined states of individual type-II GaSb/GaAs quantum rings studied by crosssectional scanning tunneling spectroscopy
R. Timm, H. Eisele, A. Lenz, L. Ivanova, V. Vossebürger, T. Warming, D. Bimberg,
I. Farrer, D.A. Ritchie, and M. Dähne
NanoLetters 10, 3972 (2010)
15.
Effect of the shape of InAs nanostructures on the characteristics of InP-based
buried heterostructure semiconductor optical amplifiers
D. Franke, J. Kreissl, W. Rehbein, F. Wenning, H. Kuenzel, U.W. Pohl,
and D. Bimberg
Appl. Phys. Express 4, 014101 (2010)
16.
Exciton fine-structure splitting in GaN/AlN quantum dots
C. Kindel, S. Kako, T. Kawano, H. Oishi, Y. Arakawa, G. Hönig, M. Winkelnkemper,
A. Schliwa, A. Hoffmann, and D. Bimberg
17.
Experimental investigation and modeling of the fine structure splitting of neutral
excitons in strain-free GaAs/AlxGa1-xAs quantum dots
J.D. Plumhof, V. Křápek, L. Wang, A. Schliwa, D. Bimberg, A. Rastelli,
and O.G. Schmidt
18.
In(Ga)As quantum dots grown on GaAs(111) substrates for entangled photons
pairs
I.A. Ostapenko, E. Stock, T. Warming, S. Rodt, A. Schliwa, M. Öztürk, J.A. Töfflinger,
A. Lochmann, D. Bimberg, A.I. Toropov, S.A. Moshchenko, D.V. Dmitriev,
V A. Haisler
Journal of Physics: Conf. Ser. (Robert A Taylor, Ed.) 245, 012003 (2010)
19.
Large internal dipole moment in InGaN/GaN quantum dots
I. A. Ostapenko, G. Hönig, C. Kindel, S. Rodt, A. Strittmatter, A. Hoffmann,
D. Bimberg
Appl. Phys. Lett. 97, 063103 (2010)
53
20.
Nachruf auf Ulrich M. Gösele
D. Bimberg, O. Engström, H. Föll, F. Spaepen, K. Urban, E. Weber
Physik Journal 9, 48 (2010)
21.
Optical imaging of electrical carrier injection into individual InAs quantum dots
A. Baumgartner, E. Stock, A. Patanè, L. Eaves, M. Henini, and D. Bimberg
Physical Review Letters 105, 257401 (2010)
22.
Photon statistics of a single quantum dot in a microcavity
Y. Su, M. Richter, A. Knorr, D. Bimberg, and A. Carmele
Physica Status Solidi - Rapid Research Letters 4, 289 (2010)
23.
Self-organized quantum dots for single photon emitters
E. Stock
Proc. of 18th Int. Symp. “Nanostructures: Physics and Technology”, St. Petersburg,
Russia, June 2010 (Zh.I. Alferov, L. Esaki, Eds.), 359 (2010)
24.
Semiconductor quantum dots: Same, same, but different
D. Bimberg
International Symposium Semiconductor Heterostructures:, St. Petersburg, March 2010
(2010)
25.
Single photon sources based on semiconductor quantum dots
D. Bimberg, E. Stock
Photonics Society Winter Topicals Meeting Series (WTM), 2010 IEEE , 141 (2010)
26.
Single-photon emission from InGaAs quantum dots grown on (111) GaAs
E. Stock, T. Warming, I. Ostapenko, S. Rodt, A. Schliwa, J.A. Töfflinger, A.
Lochmann, A.I. Toropov, S.A. Moshchenko, D.V. Dmitriev, V.A. Haisler,
and D. Bimberg
Appl. Phys. Lett. 96, 093112 (2010)
27.
Theory of single quantum dot lasers: Pauli-blocking-enhanced anti-bunching
Y. Su, A. Carmele, M. Richter, K. Lüdge, E. Schöll, D. Bimberg and A. Knorr
Semiconductor Science Technology 26 (1), 014015 (2010)
28.
Time-resolved amplified spontaneous emission in quantum dots
J. Gomis-Bresco, S. Dommers-Völkel, O. Schöps, Y. Kaptan, O. Dyatlova, D. Bimberg,
and U. Woggon
Appl. Phys. Lett. 97, 251106 (2010)
b)
Surface Emitters: VCSELs, Single Entangled Photon Emitters, Silicon Photonics
29.
120°C 20 Gbit/s operation of 980 nm VCSEL based on sub-monolayer growth
F. Hopfer, A. Mutig, G. Fiol, P. Moser, D. Arsenijević, V.A. Shchukin, N.N. Ledentsov,
S.S. Mikhrin, I.L. Krestnikov, D.A. Livshits, A.R. Kovsh, M. Kuntz, and D. Bimberg
Proc. of SPIE: Vertical-Cavity Surface-Emitting Lasers XIII (K. D. Choquette, Chun
Le, Eds.) 7229, 710 (2009)
54
30.
20 Gbit/s error free transmission with ~850 nm GaAs-based vertical cavity surface
emitting lasers (VCSELs) containing InAs-GaAs submonolayer quantum dot
insertions
J.A. Lott, V.A. Shchukin, N.N. Ledentsov, A. Stinz, F. Hopfer, A. Mutig, G. Fiol,
D. Bimberg, S.A. Blokhin, L.Y. Karachinsky, I.I. Novikov, M.V. Maximov,
N.D. Zakharov, and P. Werner
Proc. of SPIE: Physics and Simulation of Optoelectronic Devices XVII (M. Osinski,
B. Witzigmann, F. Henneberger, Y. Arakawa, Eds.) 7211, 721114 (2009)
31.
22 Gb/s long wavelength VCSELs
W. Hofmann, M. Müller, A. Nadtochiy, C. Meltzer, A. Mutig, G. Böhm, J. Rosskopf,
D. Bimberg, M.-C. Amann, and C. Chang-Hasnain
Optics Express 17, 17547 (2009)
32.
32 Gbit/s multimode fibre transmission using high-speed, low current density 850
nm VCSEL
P. Westbergh, J.S. Gustavsson, A. Haglund, A. Larsson, F. Hopfer, G. Fiol,
D. Bimberg, and A. Joel
Electronics Letters 45, 366 (2009)
33.
Electrically pumped, micro-cavity based single photon source driven at 1 GHz
A. Lochmann, E. Stock, J.A. Töfflinger, W. Unrau, A. Toropov, A. Bakarov,
V. Haisler, and D. Bimberg
34.
Frequency response of large aperture oxide-confined 850 nm vertical cavity
surface emitting lasers
A. Mutig, S.A. Blokhin, A.M. Nadtochiy, G. Fiol, J.A. Lott, V.A. Shchukin,
N.N. Ledentsov, and D. Bimberg
Appl. Phys. Lett. 95, 131101 (2009)
35.
Modeling highly efficient RCLED-type quantum dot based single photon emitters
M.C. Münnix, A. Lochmann, D. Bimberg, and V.A. Haisler
IEEE Journal of Quantum Electronics 45, 1084 (2009)
36.
Oxide-confined 850 nm VCSELs operating at bit rates up to 40 Gbit/s
S.A. Blokhin, J.A. Lott, A. Mutig, G. Fiol, N.N. Ledentsov, M.V. Maximov,
A.M. Nadtochiy, V.A. Shchukin, and D. Bimberg
37.
Polarization switching in quantum-dot vertical-cavity surface-emitting lasers
L. Olejniczak, M. Sciamanna, H. Thienpont, K. Panajotov, A. Mutig, F. Hopfer,
and D. Bimberg
IEEE Photonics Technology Letters 21, 1008 (2009)
38.
Temperature-dependent small-signal analysis of high-speed high-temperature
stable 980 nm VCSELs
A. Mutig, G. Fiol, K. Pötschke, P. Moser, D. Arsenijević, V.A. Shchukin, N.N.
Ledentsov, S.S. Mikhrin, I.L. Krestnikov, D.A. Livshits, A.R. Kovsh, F. Hopfer,
and D. Bimberg
IEEE Journal of Selected Topics in Quantum Electronics 15, 679 (2009)
55
39.
1.55 µm high-speed VCSELs enabling error-free fiber-transmission up to 25 Gbit/s
M. Müller, W. Hofmann, A. Nadtochiy, A. Mutig, G. Bohm, M. Ortsiefer, D. Bimberg,
and M.-C. Amann
Proc. of Int. Semiconductor Laser Conference (ISLC 2010), Kyoto, Japan, September
2010 , 156 (2010)
40.
40 Gbit/s error-free operation of oxide-confined 850 nm VCSEL
P. Westbergh, J.S. Gustavsson, B. Kögel, A. Haglund, A. Larsson, A. Mutig,
A. Nadtochiy, D. Bimberg and A. Joel
41.
850 nm VCSEL operating error-free at 40 Gbit/s
P. Westbergh, J.S. Gustavsson, B. Kögel, Å. Haglund, A. Larsson, A. Mutig,
A. Nadtochiy, and D. Bimberg
Proc. of Int. Semiconductor Laser Conference (ISLC 2010), Kyoto, Japan,
September 2010 , 154 (2010)
42.
A small form-factor and low-cost opto-electronic package for short-reach 40 Gbit/s
serial speed optical data links
J.- R. Kropp, J.A. Lott, N.N. Ledentsov, P. Otruba, K. Drögemüller, G. Fiol,
D. Bimberg, I. Ndip, R. Erxleben, U. Maaß, M. Klein, G. Lang, H. Oppermann,
H. Schröder and H. Reichl
Electronic System-Integration Technology Conference (ESTC), (2010)
43.
Characteristics of metal-cavity surface-emitting microlaser
C.-Y. Lu, S.-W. Chang, and S. L. Chuang, T.D. Germann, U.W. Pohl, and D. Bimberg
2010 IEEE Photonics Society 23rd Annual Meeting IEEE Catalog: CFP10LEO (CDR),
240 (2010)
44.
Comparison between two types of photonic-crystal cavities for single photon
emitters
W. Fan, Z. Hao, E. Stock, J. Kang, Y. Luo, and D. Bimberg
45.
CW substrate-free metal-cavity surface microemitters at 300 K
C.-Y. Lu, S.-W. Chang, S.L. Chuang, T.D Germann, U.W. Pohl and D. Bimberg
46.
Evolution of high-speed long-wavelength vertical-cavity surface-emitting lasers
W. Hofmann
47.
Frequence response of oxide-confined 850 nm VCSELs
S.A. Blokhin, A. Mutig, A.M. Nadtochiy, G. Fiol, J.A. Lott, V.A. Shchukin,
N.N. Ledentsov, D. Bimberg
Proc. of 18th Int. Symp. “Nanostructures: Physics and Technology”, St. Petersburg,
Russia, June 2010 (Zh.I. Alferov, L. Esaki, Eds.), 35 (2010)
56
48.
Highly temperature-stable modulation characteristics multioxide-aperture highspeed 980 nm vertical cavity surface emitting lasers
A. Mutig, J.A. Lott, S.A. Blokhin, P. Wolf, P. Moser, W.A.M. Nadtochiy, A. Payusov,
and D. Bimberg
Appl. Phys. Lett. 97, 151101 (2010)
49.
High-speed 850 nm oxide confined VCSELs for DATACOM applications
A. Mutig, S.S. Blokhin, A.A. Nadtochiy, G. Fiol, J.A. Lott, V.A. Shchukin,
N.N. Ledenstov, D. Bimberg
Proc. of SPIE: Vertical-Cavity Surface-Emitting Lasers XIV, edited by James
K. Guenter, Kent D. Choquette 7615, 76150N (2010)
50.
High-speed 850 nm VCSELs for 40 Gb/s transmission
J. Gustavsson, P. Westbergh, K. Szczerba, Å. Haglund, A. Larsson, M. Karlsson,
P. Andrekson, F. Hopfer, G. Fiol, D. Bimberg, B.-E. Olsson, A. Kristiansson, S. Healy,
E. O'Reilly, A. Joel
Proc. of SPIE: Semiconductor Lasers and Laser Dynamics IV (Krassimir Panajotov;
Marc Sciamanna; Angel A. Valle; Rainer Michalzik, Eds.) 7720, 772002 (2010)
51.
High-speed 980 nm VCSELs for very short reach optical interconnects
A. Mutig, J. Lott, S. Blokhin, P. Moser, P. Wolf, W. Hofmann, A. Nadtochiy,
A. Payusov, and D. Bimberg
September 2010 , 158 (2010)
52.
High-speed single-photon source based on self-organized quantum dots
E. Stock, W. Unrau, A. Lochmann, J. A. Töfflinger, M. Öztürk, A.I. Toropov,
A.K. Bakarov, V.A. Haisler and D. Bimberg
53.
Metal-cavity surface-emitting microlaser at room temperature
C.-Y. Lu, S.-W. Chang, S. L. Chuang, T.D. Germann, and D. Bimberg
Appl. Phys. Lett. 96, 251101 (2010)
54.
Monolithic electro-optically modulated vertical cavity surface emitting laser with
10 Gb/s open-eye operation
T. D. Germann A. Strittmatter A. Mutig A.M. Nadtochiy J.A. Lott S.A. Blokhin
L.Ya. Karachinsky V.A. Shchukin N.N. Ledentsov U.W. Pohl and D. Bimberg
Physica Status Solidi C 7 (10), 2552 (2010)
55.
Optical components for very short reach applications at 40 Gb/s and beyond
N.N. Ledentsov, J.A. Lott, V.A. Shchukin, A. Mutig, T.D. Germann, S.A. Blokhin,
A.M. Nadtochiy, L.Y. Karachinsky, D. Bimberg
Proc. of SPIE: Physics and Simulation of Optoelectronic Devices XVIII, edited by
Bernd Witzigmann, Fritz Henneberger, Yasuhiko Arakawa, Marek Osinski 7597,
7597F (2010)
56.
Oxide confined 850 nm VCSELs for high speed datacom applications
P. Moser, A. Mutig, J.A. Lott, S.A. Blokhin, G. Fiol, A.M. Nadtochiy, N.N. Ledentsov
and D. Bimberg
Marc Sciamanna; Angel A. Valle; Rainer Michalzik, Eds.) 7720, 77201W (2010)
57
57.
Polarization switching and polarization mode hopping in quantum dot verticalcavity surface-emitting lasers
L. Olejniczak, K. Panajotov, H. Thienpont, M. Sciamanna, A. Mutig, F. Hopfer,
D. Bimberg
Marc Sciamanna; Angel A. Valle; Rainer Michalzik, Eds.) 7720, 77201G (2010)
58.
Quantum dots for single and entangled photon emitters
E. Stock, D. Bimberg, A. Lochmann, A. Schliwa, W. Unrau, M. Münnix, S. Rodt,
A.I. Toropov, A. Bakarov, A.K. Kalagin, and V.A. Haisler
Proc. of SPIE: Quantum Dots and Nanostructures: Synthesis, Characterization, and
Modeling VII, Kurt G. Eyink, Frank Szmulowicz, Diana L. Huffaker (Eds.) 7610,
7610G (2010)
59.
Substrate-free metal cavity surface-emitting laser with CW operation at room
temperature
C.-Y. Lu, S.-W. Chang, and S.L. Chuang, T.D. Germann and D. Bimberg
September 2010 , 15 (2010)
60.
Ultrafast VCSELs for Datacom
D. Bimberg
IEEE Photonics Journal 2, 273 (2010)
c)
Edge Emitters: High-Frequency Lasers and Amplifiers, High-Brightness Lasers
61.
High-brightness and ultranarrow-beam 850 nm GaAs/AlGaAs photonic band
crystal lasers and single-mode arrays
T. Kettler, K. Posilovic, L.Ya. Karachinsky, P. Ressel, A. Ginolas, J. Fricke, U.W.Pohl,
V.A. Shchukin, N.N. Ledentsov, D. Bimberg, J. Jönsson, M. Weyers, G. Erbert, and
G. Tränkle
62.
High-speed small-signal cross-gain modulation in quantum-dot semiconductor
optical amplifiers at 1.3 µm
C. Meuer, J. Kim, M. Laemmlin, S. Liebich, G. Eisenstein, R. Bonk, T. Vallaitis,
J. Leuthold, A. Kovsh, I. Krestnikov, and D. Bimberg
63.
Quantum dot semiconductor lasers of the 1.3 µm wavelength range with high
temperature stability of the lasing wavelength (0.2 nm/K)
L.Ya. Karachinsky, I.I. Novikov, Y.M. Shernyakov, N.Y. Gordeev, A.S. Payusov,
M.V. Maximov, S.S. Mikhrin, M.B. Lifshits, V.A. Shchukin, P.S. Kop'ev,
N.N. Ledentsov, and D. Bimberg
Semiconductors 43, 680 (2009)
64.
Quantum-dot semiconductor mode-locked lasers and amplifiers at 40 GHz
G. Fiol, C. Meuer, H. Schmeckebier, D. Arsenijević, S. Liebich, M. Laemmlin,
M. Kuntz, and D. Bimberg
58
65.
Role of carrier reservoirs on the slow phase recovery of quantum dot
semiconductor optical amplifiers
J. Kim, C. Meuer, D. Bimberg, and G. Eisenstein
Appl. Phys. Lett. 94, 41112 (2009)
66.
Small-signal cross-gain modulation and crosstalk characteristics of quantum-dot
semiconductor optical amplifiers at 1.3 µm
J. Kim , M. Laemmlin, C. Meuer, S. Liebich, D. Bimberg, and G. Eisenstein
Phys. Stat. Sol. (b) 246, 864 (2009)
67.
Theoretical and experimental study of high-speed small-signal cross-gain
modulation of quantum-dot semiconductor optical amplifiers
J. Kim, M. Laemmlin, C. Meuer, D. Bimberg, G. Eisenstein
68.
Ultrahigh speed nanophotonics
D. Bimberg, G. Fiol, C. Meuer, D. Arsenijević, J. Kim, S. Liebich, M. Laemmlin,
M. Kuntz, H. Schmeckebier, and G. Eisenstein
Proc. of SPIE: Physics and Simulation of Optoelectronic Devices XVII (M. Osinski,
B. Witzigmann, F. Henneberger, Y. Arakawa, Eds.) 7211, 721117 (2009)
69.
1.3 µm range 40 GHz quantum-dot mode-locked laser under external continuous
wave light injection or optical feedback
G. Fiol, M. Kleinert, D. Arsenijević and D. Bimberg
70.
10.7 W peak power picosecond pulses from high-brightness photonic band crystal
laser diode
S. Riecke, K. Posilovic, T. Kettler, D. Seidlitz, V.A. Shchukin, N.N. Ledentsov,
K. Lauritsen and D. Bimberg
71.
40 GHz and 160 GHz mode-locked quantum-dot laser showing pulse width of 750
fs at 1.3 µm
H. Schmeckebier, G. Fiol, C. Meuer, D. Arsenijević, D. Bimberg
Marc Sciamanna; Angel A. Valle; Rainer Michalzik, Eds.) 7720, 772010 (2010)
72.
80 Gb/s multi-wavelength booster amplification in an InGaAs/GaAs quantum-dot
semiconductor optical amplifier
C. Schmidt-Langhorst, C. Meuer, A. Galperin, H. Schmeckebier, R. Ludwig, D. Puris,
D. Bimberg, K. Petermann, C. Schubert
Proc. of ECOC 2010 - European Conference and Exhibition on Optical Communication
IEEE Catalog Number: CFP10425-ART, Mo.1.F.6 (2010)
73.
Complete pulse characterization of quantum-dot mode-locked lasers suitable for
optical communication up to 160 Gbit/s
H. Schmeckebier, G. Fiol, C. Meuer, D. Arsenijević, and D. Bimberg
Optics Express 18, 3415 (2010)
59
74.
Cross-gain modulation and four-wave mixing for wavelength conversion in
undoped and p-doped 1.3-µm quantum dot semiconductor optical amplifiers
C. Meuer, H. Schmeckebier, G. Fiol, D. Arsenijević, J. Kim, G. Eisenstein, D. Bimberg
IEEE Photonics Journal 2, 141 (2010)
75.
Dynamical regimes in a monolithic passively mode-locked quantum dot laser
A.G. Vladimirov, U. Bandelow, G. Fiol, D. Arsenijević, M. Kleinert, D. Bimberg,
A. Pimenov, and D. Rachinskii
Journal of the Optical Society of America B-Optical Physics 27, 2102 (2010)
76.
Effect of inhomogeneous broadening on gain and phase recovery of quantum-dot
77.
Finite element simulation of the optical modes of semiconductor lasers
J. Pomplun, S. Burger, F. Schmidt, A. Schliwa, D. Bimberg, A. Pietrzak, H. Wenzel,
and G. Ebert
Physica Status Solidi B 247, 846 (2010)
78.
Four-wave mixing in 1.3 µm quantum-dot semiconductor optical amplifiers
D. Bimberg, C. Meuer, G. Fiol, H. Schmeckebier and D. Arsenijević
Proc. of ICTON 2010 IEEE Catalog Number: CFP10485-USB (CD-ROM), We.D4.21
(2010)
79.
High-power high-brightness semiconductor lasers based on novel waveguide
concepts
D. Bimberg, K. Posilovic, V. Kalosha, T. Kettler, D. Seidlitz, V.A. Shchukin,
N.N. Ledentsov, N.Y. Gordeev, L.Y. Karachinsky, I.I. Novikov, M.V. Maximov,
Y.M. Shernyakov, A.V. Chunareva, F. Bugge, M. Weyers
Proc. of SPIE: Novel In-Plane Semiconductor Lasers IX, edited by Alexey A. Belyanin,
Peter M. Smowton 7616, 76161 (2010)
80.
Hybrid mode-locking in a 40 GHz monolithic quantum dot laser
G. Fiol, D. Arsenijević, D. Bimberg, A.G. Vladimirov, M. Wolfrum, E.A. Viktorov, and
P. Mandel
Appl. Phys. Lett. 96, 011104 (2010)
81.
Influence of the pump wavelength on the gain and phase recovery of quantum-dot
82.
Large-signal response of semiconductor quantum-dot lasers
K. Ludge, R. Aust, G. Fiol, M. Stubenrauch, D. Arsenijević, D. Bimberg, and E. Schöll
83.
Linear and nonlinear semiconductor optical amplifiers
J. Leuthold, R. Bonk, T. Vallaitis, A. Marculescu, W. Freude, C. Meuer, D. Bimberg,
R. Brenot, F. Lelarge, G.-H. Duan
Optical Fiber Communication Conference, OSA Technical Digest (CD) (2010)
60
84.
Linear and nonlinear semiconductor optical amplifiers
W. Freude, R. Bonk, T. Vallaitis, A. Marculescu, A. Kapoor, E.K. Sharma, C. Meuer,
D. Bimberg, R. Brenot, F. Lelarge, G.-H. Duan, C. Koos, J. Leuthold
Proc. of ICTON 2010 IEEE Catalog Number: CFP10485-USB (CD-ROM), We.D4.11
(2010)
85.
Locking characteristics of a 40GHz hybrid mode-locked monolithic quantum dot
laser
A.G. Vladimirov, M. Wolfrum, G. Fiol, D. Arsenijević, D. Bimberg, E. Viktorov,
P. Mandel, D. Rachinskii
Marc Sciamanna; Angel A. Valle; Rainer Michalzik, Eds.) 7720, 77200Y (2010)
86.
Looking on the bright side
S. Riecke, K. Posilovic, T. Kettler, D. Seidlitz, V.A. Shchukin, N.N. Ledentsov,
K. Lauritsen and D. Bimberg
87.
Modeling of photonic crystal based high power high brightness semiconductor
lasers
V. Shchukin, N. Ledentsov, V. Kalosha, T. Kettler, K. Posilovic, D. Seidlitz ,
D. Bimberg, N.Yu. Gordeev, L.Ya. Karachinsky, I.I. Novikov, Y.M. Shernyakov,
A.V. Chunareva, M.V. Maximov
Proc. of SPIE: Physics and Simulation of Optoelectronic Devices XVIII, edited by
Bernd Witzigmann, Fritz Henneberger, Yasuhiko Arakawa, Marek Osinski 7597,
75971A (2010)
88.
Numerical simulation of temporal and spectral variation of gain and phase
recovery in quantum-dot semiconductor optical amplifiers
89.
Optical and electrical power dynamic range of semiconductor optical amplifiers in
radio-over-fiber networks
S. Koenig, J. Pfeifle, R. Bonk, T. Vallaitis, C. Meuer, D. Bimberg, C. Koos, W. Freude,
J. Leuthold
Proc. of ECOC 2010 - European Conference and Exhibition on Optical Communication
IEEE Catalog Number: CFP10425-ART, Th.10.B.6 (2010)
90.
Quantum dot semiconductor optical amplifiers at 1.3 µm for applications in alloptical communication networks
H. Schmeckebier, C. Meuer, D. Bimberg, C. Schmidt-Langhorst, A. Galperin, and
C. Schubert
91.
Tilted waveguide and PBC lasers: Novel cavity designs for narrow far-fields and
high brightness
D. Bimberg, K. Posilovic, V. Kalosha, T. Kettler, D. Seidlitz, V.A. Shchukin,
N.N. Ledentsov, S. Riecke, K. Lauritsen, F. Bugge and M. Weyers
2010 IEEE Photonics Society 23rd Annual Meeting IEEE Catalog: CFP10LEO (CDR),
475 (2010)
61
d)
Nanoflash Memories
92.
A novel nonvolatile memory based on self-organized quantum dots
A. Marent, M. Geller, D. Bimberg
Microelectronics Journal 40, 492 (2009)
93.
Hole-based memory operation in an InAs/GaAs quantum dot heterostructure
A. Marent, T. Nowozin, J. Gelze, F. Luckert, and D. Bimberg
Appl. Phys. Lett. 95, 242114 (2009)
94.
Temperature and electric field dependence of the carrier emission processes in a
quantum dot-based memory structure
T. Nowozin, A. Marent, M. Geller, D. Bimberg, N. Akçay, and N. Öncan
Appl. Phys. Lett. 94, 42108 (2009)
95.
Nanomemories using self-organized quantum dots
M. Geller, A. Marent, D. Bimberg
Handbook of Nanophotonics. Nanoelectronics and Nanophotonics (K. Sattler, ed.),
chapter 2 (2010)
96.
The QD-Flash: A quantum dot-based memory device
A. Marent, T. Nowozin, M. Geller and D. Bimberg
Semiconductor Science and Technology 26, 14026 (2010)
e)
Magnetic Resonance Investigations
97.
Magnetic and structural properties of transition metal doped zinc-oxide
nanostructures
A.O. Ankiewicz, W. Gehlhoff, J.S. Martins, A.S. Pereira, S. Pereira, A. Hoffmann,
E.M. Kaidashev, A. Rahm, M. Lorenz, M. Grundmann, M.C. Carmo, T. Trindade,
N.A. Sobolev
Phys. Stat. Sol. (b) 4, 766 (2009)
98.
EPR identification of intrinsic and transition metal-related defects in ZnGeP2 and
other II-IV-V2 compounds
W. Gehlhoff, A. Hoffmann
Physica B 404, 4942 (2009)
99.
EDEPR of impurity centers embedded in silicon microcavities
N.T. Bagraev, W. Gehlhoff, D.S. Gets, L.E. Klyachkin, A.A. Kudryavtsev,
A.M. Malyarenko, V.A. Mashkov, V.V. Romanov
Physica B 404, 5140 (2009)
100. A systematic study on zinc oxide materials containing group I metals (Li, Na,K) Synthesis from organometallic precursors, characterization, and properties
S. Polarz, A. Orlov, A. Hoffmann, M.R. Wagner, C. Rauch, R. Kirste, W. Gehlhoff,
Y. Aksu, M. Driess, M.W.E. van den Berg, and M. Lehmann
Chemistry of Materials 21, 3889 (2009)
62
101. Lithium related deep and shallow acceptors in Li-doped ZnO nanocrystals
C. Rauch, W. Gehlhoff, M. R. Wagner, E. Malguth, G. Callsen, R. Kirste, B. Salameh,
A. Hoffmann, S. Polarz, Y. Aksu, and M. Driess
Journal of Applied Physics 107, 24311 (2010)
102. EDESR and ODMR of impurity centers in nanostructures inserted in silicon
microcavities
N.T. Bagraev, V.A. Mashkov, E.Yu. Danilovsky, W. Gehlhoff, D.S. Gets,
L.E. Klyachkin, A.A. Kudryavtsev, R.V. Kuzmin, A.M. Malyarenko und
V.V. Romanov
Applied Magnetic Resonance 39, 113 (2010)
63
9.1.4 Invited Talks
D. Bimberg
Ultrahigh speed nanophotonics
IEEE/LEOS Winter Topical Meeting Series on Nonlinear Dynamics
in Photonics Systems, Innsbruck, Austria, January 2009
D. Bimberg
Nano-VCSELs for the terabus
17th International Symposium Nanostructures: Physics and
Technology, Minsk, Belarus, June 2009
D. Bimberg
High speed single photon emitters for quantum communication,
Rusnanotech 2009 - The Second Nanotechnology International
Forum, Moscow, Russia, October 2009
D. Bimberg
Quantum dots for single and entangled photon emitters
Conference 7610: Quantum Dots and Nanostructures: Synthesis,
Characterization, and Modeling VII at SPIE Photonics West,
San Francisco, California, USA, January 2010
D. Bimberg
High-power high-brightness semiconductor lasers based on novel
concepts
Conference 7616: Novel In-Plane Semiconductor Lasers IX at SPIE
Photonics West,
San Francisco, California, USA, January 2010
D. Bimberg
Our daily life with semiconductor lasers
DPG Frühjahrstagung der Sektion AMOP,
Hannover, Germany, March 2010
D. Bimberg
Semiconductor quantum dots: Same, same, but different
International Symposium Semiconductor Heterostructures:
Physics, Technology, Applications,
St. Petersburg, Russia, March 2010
D. Bimberg
DPG-Frühjahrstagung der Sektion Kondensierte Materie (SKM),
D. Bimberg
Flying Q-bits and entangled photons enabling quantum
cryptography
2010 Villa Conference on Interaction Among Nanostructures
(VCIAN-2010) Santorini, Greece, June 2010
D. Bimberg
International Nano-Optoelectronic Workshop, ( iNow 2010),
Beijing and Changchun, China, August 2010
64
D. Bimberg
Nanophotonics for future Datacom and Ethernet networks
International Workshop on High Speed Semiconductor Lasers
(HSSL), Wroclaw, Poland, October 2010
D. Bimberg
Tilted waveguide and PBC lasers: Novel cavity designs for narrow
far-fields and high brightness
IEEE Photonics Society 23rd Annual Meeting,
Denver, USA, November 2010
S.L. Chuang
Metal-cavity nanolasers
2010 Villa Conference on Interaction Among Nanostructures
(VCIAN-2010) Santorini, Greece, June 2010
G. Fiol
QD monolithic mode locked lasers
Nonlinear Dynamics in Quantum Dot Devices (Minisymposium)
Weierstrass Institute for Applied Analysis and Stochastics (WIAS),
Berlin, Germany, November 2009
T. Germann
MOVPE of a metal-cavity surface-emitting laser operating CW
at room-temperature
15th International Conference on Metal Organic Vapor Phase Epitaxy,
Lake Tahoe, USA, May 2010
W. Hofmann
Long-wavelength vertical-cavity surface-emitting lasers with a
high-contrast grating
V. Kalosha
High-brightness edge-emitting semiconductor lasers based on
concepts of photonic band crystal and titled wave lasers
A. Lochmann
Cavity-enhanced emission in electrically driven quantum dot
single-photon-emitters
SPIE-Europe Microtechnologies for the New Millenium, (EMT-09),
Dresden, Germany, May 2009
A. Marent
Quantum dot flash memories: The best of two worlds
A. Marent
Self-organized quantum dots for novel nano-memories
International Conference on Superlattices, Nanostructures and
Nanodevices (ICSNN-2010), Beijing, China, July 2010
65
C. Meuer
Influence of p-doping in quantum dot semiconductor optical
amplifiers at 1.3 μm
11th International Conference on Transparent Optical Networks
(ICTON 2009), S. Miguel, Azores, Portugal, June/July 2009
C. Meuer
Four-wave mixing in 1.3 µm quantum-dot semiconductor optical
amplifiers
12th International Conference on Transparent Optical Networks
(ICTON 2010), München, Germany, June 2010
A. Mutig
Nano-VCSELs for the Terabus
17th International Symposium "Nanostructure: Physics and
Technology"
St. Petersburg, Russia, June 2009
A. Mutig
High-speed 850 nm oxide confined VCSELs for DATACOM
applications
Conference 7615: Vertical-Cavity Surface-Emitting Lasers XIV at
SPIE Photonics West, San Francisco, California, USA, January 2010
U. Pohl
Metal-cavity surface-emitting microlaser
Int. Conf. on the Physics of Semiconductors (ICPS 2010), Seoul,
Korea, July 2010
A. Schliwa
Single photon sources based on semiconductor quantum dots
WTM 2010 IEEE Photonics Society Winter Topical on
Semiconductor Nanolasers, Palma de Mallorca, Spain, January 2010
H. Schmeckebier
160 GHz sub-picosecond mode-locked quantum-dot laser pulses
European Semiconductor Laser Workshop 2010, Pavia, Italy,
September 2010
A. Strittmatter
Green light-emitting diodes and laser heterostructures on semipolar GaN(11-22)/sapphire substrates
E. Stock
Self-organized quantum dots as single and entangled photon
emitters
E. Stock
Self-organized quantum dots for single photon emitters
18th International Symposium Nanostructures: Physics and
Technology , St. Petersburg, Russia, June 2010
66
Dejan Arsenijević
Erzeugung ultrakurzer optischer Pulse mit Quantenpunktlasern
16.02.2009
Johannes Gelze
Ladungsträgerdynamik in Quantenpunkt-basierten
Speicherbausteinen
28.07.2009
Annika Högner
Quantenpunktbasierte Speicherbausteine
21.12.2010
Gerald Hönig
Mehrteilchen-Zustände in Nitrid-basierten Quantenpunkten
16.10.2009
Benjamin Mayer
Automatisierte Erfassung der Fundamentaldaten von
VCSEL-Wafern
22.10.2010
Gang Lou
Epitaxie vergrabener GaAs-basierter Laserstrukturen
18.10.2009
Holger Schmeckebier
Analyse von optischen Pulsen modengekoppelter
Quantenpunkt-Halbleiterlaser
19.06.2009
Daniel Seidlitz
Wellenlängenstabilisierte Halbleiterlaser auf Basis neuer
Wellenleiterkonzepte
15.01.2010
Jan Amaru Töfflinger
Quantenpunkte für Einzelphotonenemitter
18.03.2010
Peter Benedikt Weber
High-speed vertical cavity emitting lasers
03.06.2009
Philip Wolf
Prozessierung und Charakterisierung von oberflächenemittierenden Lasern
08.07.2010
67
9.2. Department II
Department IIa: Prof. Dr. rer. nat. Christian Thomsen
Department IIb: Prof. Dr. rer. nat. Janina Maultzsch
Department IIc: Prof. Dr. Axel Hoffmann
9.2.a Department IIa
9.2a.1 Staff
Secretary
Mandy Neumann
Technical Staff
Sabine Morgner
Ing.grad. Heiner Perls
Michael Mayer
Senior Scientists
Dr. Dirk Heinrich
Dr. Holger Lange
Dr. Marcel Mohr
Dr. Niculina Peica
Dr. Harald Scheel
Dr. Andrei Schliwa
PhD Candidates (status of 31.12.2010: thesis completed = c)
Dipl.-Phys. Sevak Khachadorian
Dipl.-Phys. Marcel Mohr (c)
Dipl.-Phys. Matthias Müller (c)
Dipl.-Phys. Grit Petschick
Dipl.-Phys. Nils Rosenkranz
Dipl.-Phys. Andrei Schliwa (c)
Dipl.-Phys. Norman Tschirner
68
Diploma and Teacher Students (status of 31.12.2010: thesis completed = c)
Jeffrey Bronsert
Juri Brunnmeier
Max Bügler (c)
Ralf Dornath
Sebastian Gade
Roland Gillen
Stefan Grützner
Frederike Kneer
Ronny Kirste (c)
Thomas Kure
Jakob Löber
Andreas Moschini
Felix Nippert
Christian Nitschke
Nadine Oswald
Thomas Plocke (c)
Nils Scheuschner
Maria-Astrid Schröter
Moritz Schubotz
Franz Schulze
Sebastian Siewert
Sergej Solopow
Matthias Sturm
Mehmet Can Ucar
Asmus Vierck
Mario Wegner
Marina Zajnulina
69
9.2a.2 Summary of Activities
The activity of this group is centered on optical spectroscopy of carbon nanotubes, wide and
narrow-gap semiconductors nanostructures, 2D electron gases, quantum dots, semiconductor
core-shell nanodots and ferrofluids. Emphasis in the work on carbon nanotubes was put on
the understanding of the electroni properties and how they compare to those of graphene and
graphene nanoribbons. There is close collaboration with the group of Prof. Janina Maultzsch
on these topics. As part of the investigations in the Cluster of Excellence “Catalysis” we
expanded our investigations to functionalized carbon nanotubes. In the nanostructure-related
project of the Sonderforschungsbereich 787 investigations focused on Raman and firspectroscopy of quantum dots and their luminescence properties as far as they are related to
device applications. Our investigations of Si nanowires covered the difference on properties
of nanowires compared to the bulk material. We investigated Si nanowires under large
hydrostatic pressure. Our work on surfacted ferrofluids continues. In this period we covered
mostly the behavior of ion-stabilized ferrofluids in an applied magnetic field. These fluids aside from physics research - are of interest for medical applications.
We continued to expand our laboratory with remotely controlled experiments (remoteFarm)
which are used in the education of – in particular – engineering students. These experiments
are controlled over the internet and available on a 24/7 basis. Modern control and evaluation
software allow experimenting from a remote location and contribute to the excellence in
teaching at TU Berlin. Our remoteFarm is increasingly becoming used in international
projects as best practice laboratory.
70
9.2a.3 Publications
1.
Theory of multiwall carbon nanotubes as waveguides and antennas in the infrared
and the visible regimes
M. V. Shuba, G. Ya. Slepyan, S. A. Maksimenko, C. Thomsen, A. Lakhtakia
Phys. Rev. B 79, 155403 (2009)
2.
Geometry dependence of the phonon modes in CdSe nanorods
Holger Lange, Mikhail Artemyev, Ulrike Woggon, Christian Thomsen
Nanotechnology 20, 045705 (2009)
3.
Carbon nanotube as a nanoscale Cherenkov-type light emitter – nanoFEL
K. G. Batrakov, S.A. Maksimenko, P.P. Kuzhir, C. Thomsen
Phys. Rev. B 79, 125408 (2009)
4.
Phonons in bulk CdSe and CdSe nanowires
M. Mohr and C. Thomsen
5.
Geometry dependence of the phonon modes in CdSe nanorods
Holger Lange, Mikhail Artemyev, Ulrike Woggon, Christian Thomsen
6.
Longitudinal optical phonons in metallic and semiconducting carbon nanotubes
M. Fouquet, H. Telg, J. Maultzsch, Y. Wu, B. Chandra, J. Hone, T. F. Heinz, and
C. Thomsen
Phys. Rev. Lett. 102, 075501 (2009)
7.
Chemical vapor deposition of carbon layers on Si {001} substrates
T.I. Milenov, P.M. Rafailov, G.V. Avdeev, C. Thomsen
J. Optoelectronics and Advanced Materials 11, 1273-1276 (2009)
8.
Spectroscopic studies on electrochemically doped and functionalized singel-walled
carbon nanotubes
P. M. Rafailov, T. I. Milenov, M. Monev, G. V. Avdeev, C. Thomsen, U. DettlaffWeglikowska, S. Roth
J. Optoelectronics and Advanced Materials 11, 1339-1342 (2009)
9.
Vibrational properties of graphene nanoribbons by first-principles calculations
Roland Gillen, Marcel Mohr, Christian Thomsen, Janina Maultzsch
Phys. Rev. B 80, 155418 (2009)
10.
Lattice distortions in a crystal caused by doping with copper
A.V. Egorysheva, T.I. Milenov, P.M. Rafailov, C. Thomsen, R. Petrova, V.M. Skorikov
and M.M. Gospodinov
Solid State Comm. 149, 1616-1618 (2009)
11.
Resonance Raman study of the superoxide reductase from Archaeoglobus fulgidus,
E12 mutants and a ’natural variant’
S. Todorovic, J.V. Rodrigues, A.F. Pinto, C. Thomsen, P. Hildebrandt, M. Teixeira,
D.H. Murgida
Phys. Chem. Chem. Phys. 11, 1809-1815 (2009).
71
12.
Victor-spaces: virtual and remote experiments in cooperative knowledge spaces
S. Cikic, S. Jeschke, N. Ludwig, U. Sinha, C. Thomsen
in: Grid enabled remote instrumentation; Series: Signals and Communication
Technology 329-343 (2009)
13.
Networking Resources for Research and Scientific Education in Nanoscience and
Nanotechnologies
S. Jeschke, N. Natho, O. Pfeiffer, C. Thomsen
2008 International Conference on Nanoscience and Nanotechnology (Australian
Research Council, Melbourne, 2008), 234-237
14.
Acetylene: a key growth precursor for single-walled carbon nanotube forests
G. Zhong, S. Hofmann, F. Yan, H. Telg, J. Warner, D. Eder, C. Thomsen, W. Milne, J.
Robertson
J. Phys. Chem. B, 113, 17321 (2009)
15.
Two-dimensional electronic and vibrational band structure of uniaxially strained
graphene from ab initio calculations
M. Mohr, K. Papagelis, J. Maultzsch, C. Thomsen
Phys. Rev. B 80, 205410 (2009)
16.
Kohn anomaly and electron-phonon interaction at the K-derived point of the
Brillouin zone of metallic nanotubes
P. Rafailov, J. Maultzsch, C. Thomsen, U. Dettlaff-Weglikowska, S. Roth
Nano Lett. 9, 3343-3348 (2009)
17.
Resonance Raman spectra of -carotene in solution and in photosystems revisited:
an experimental and theoretical study
Norman Tschirner, Matthias Schenderlein, Katharina Brose, Eberhard Schlodder, Maria
Andrea Mroginski, Christian Thomsen and Peter Hildebrandt
Phys. Chem. Chem. Phys. 11, 11471-11478 (2009)
18.
Use of carbon nanotubes for VLSI interconnects
J. Robertson, G. Zhong, S. Hofmann, B.C. Bayer, C.S. Esconjauregui, H. Telg and C.
Thomsen
Diamond and Related Materials 18, 957-962 (2009)
19.
Thin-walled Er3+:Y2O3 nanotubes showing up-converted fluorescence
Christoph Erk, Sofia Martin Caba, Holger Lange, Stefan Werner, Christian Thomsen,
Martin Steinhart, Andreas Berger and Sabine Schlecht
Phys. Chem. Chem. Phys. 11, 3623-3627 (2009)
20.
Polariton effects in the dielectric function of ZnO excitons obtained by
ellipsometry
M. Cobet, C. Cobet, M.R. Wagner, N. Esser, C. Thomsen, and A. Hoffmann
Appl. Phys. Lett. 96, 031904 (2010)
21.
Electronic properties of propylamine-functionalized single-walled carbon
nanotubes
M. Müller, R. Meinke, J. Maultzsch, Z. Syrgiannis, F. Hauke, A. Pekker, K. Kamaras,
A. Hirsch, C. Thomsen
ChemPhysChem 11, 2444 (2010)
72
22.
Terahertz conductivity peak of composite materials containing single-wall carbon
nanotubes: theory and interpretation of experiment
G. Slepyan, M. Shuba, S. Maksimenko, C. Thomsen, A. Lakhtakia
Phys. Rev. B 81, 205423 (2010)
23.
Symmetry based analysis of the Kohn anomaly and electron-phonon interaction in
graphene and carbon nanotubes
I. Milocevic, N. Kepcija, E. Dobardzic, M. Mohr, J. Maultzsch, C. Thomsen, M.
Damnjanovic
Phys. Rev. B 81, 233410 (2010)
24.
Electron-phonon coupling in grapheme
I. Milocevic, N. Kepcija, E. Dobardzic, M. Damnjanovic M. Mohr, J. Maultzsch, C.
Thomsen
Int. J. of Modern Physics B, 24, 655-660 (2010)
25.
Observation of excitonic effects in metallic single-walled carbon nanotubes
P. May, H. Telg, G. Zhong, J. Robertson, C. Thomsen, and J. Maultzsch
Phys. Rev. B 82, 195412 (2010).
73
9.2a.4 Invited Talks
R. Gillen
Ab initio calculations of the phonon spectra of graphene
nanoribbons
Frühjahrstagung der Deutschen Physikalischen Gesellschaft, Dresden,
Germany, March 2009
R. Gillen
Vibrational properties of graphene
NanoLabFor-Project Meeting, Faculty of Physics, University of
Belgrade, Serbia, June 2009
S. Khachadorian
Deployment of Remote Experiments: OnPReX Course at TU
Berlin
IEEE-EDUCON Engineering Education Conference, Madrid, Spain,
April 2010
P. Kusch
Temperature dependent Raman scattering experiments of CdSe
nanorods
Germany, March 2009
R. Meinke
Resonant Raman scattering on chemically functionalized carbon
nanotubes
Germany, March 2009
M. Mohr
Exploring the two-dimensional Brillouin zone of the electronic
and the vibrational band structure of uniaxially strained graphene
M. Mohr
Electronic and vibrational properties of graphene under strain
International Winterschool on Electronic Properties of Novel
Materials (IWEPNM), Kirchberg, Austria, March 2010
N. Rosenkranz
Molecular Dynamics Simulations of interactin carbon pico- and
nanotubes
H. Telg
Characterization of isolated metallic and semiconducting
nanotubes by Raman spectroscopy
International Winterschool on Electronic Properties of Novel
Materials (IWEPNM), Kirchberg, Austria, March 2009
H. Telg
Characterization of isolated metallic and semiconducting
nanotubes by Raman spectroscopy
European Materials Research Society, 2009 Spring Meeting,
Strasbourg, France, June 2009
74
H. Telg
Resonant Raman spectroscopy on carbon nanotubes
Electronic and Optical Properties of Molecular Nanostructures, KIT,
Karlsruhe, Germany, June 2009
H. Telg
In situ characterization of carbon nanotubes
Technotubes Project Meeting, Paris, France, September 2009
C. Thomsen
Vibrational modes in graphene and semiconductor nanorods
Wonton 2009
Matsushima, Japan, June 2009
C. Thomsen
Phonons in graphene and carbon nanotubes
ICREA Workshop on Phonon Engineering 2010, Barcelona, Spain,
May 2010
C. Thomsen
Vibrational properties of graphene and graphene nanoribbons
Symposium “Optical and Vibrational Spectroscopies”, Queretaro,
Mexico, August 2010
M. Wagner
Magneto-optic and recombination dynamic of complex bound
excitons in homoepitaxially grown ZnO epilayers
Photonics West 2009, San Jose, USA, January 2009
75
9.2a.5 Diploma Theses
Fabian Gericke
Optische Untersuchungen an phasenveränderbaren Materialien
wie Ge2Sb2Te5 und deren Schaltverhalten
27.06.2010
Roland Gillen
Schwingungseigenschaften von Graphen Nanoribbons anhand
von ab initio Berechnungen
12.04.2009
Philipp Hummel
IR spectroscopic studies of hydrogenanes
06.01.2010
Patryk Kusch
Temperaturabhängigkeit der Scheingungseigenschaften vonCdSe
Nanorods
14.05.2010
Reinhard Meinke
Optische Übergänge in Amin-funktionalisierten KohlenstoffNanoröhren
24.07.2010
76
77
9.2.b Department IIb
9.2b.1 Staff
Secretary
Mandy Neumann
Technical Staff
Sabine Morgner
Ing.grad. Heiner Perls
Michael Mayer
Dipl.-Phys. Katharina Brose
Dipl.-Phys. Jan Laudenbach
Dipl.-Phys. Patrick May
Diploma and Teacher Students (status of 31.12.2010: thesis completed = c)
Nils Scheuschner
Felix Herziger
9.2b.2 Summary of Activities
Our research activities focus on the physical properties of nanostructures, in particular carbon
nanotubes, graphene and nanoribbons, Si clusters, as well as biomolecules such as carotene
and photosystemII. We study their optical, vibrational and electronic properties and the
interaction between their electronic and vibrational system.
Our research on carbon nanotubes focused on exciton-phonon coupling and on chemically
functionalized nanotubes. The exciton-phonon coupling strength was investigated by resonant
Raman scattering. We found a distinct dependence of the coupling strength on the chiral angle
of nanotubes (see figure), which is important to know when studying the abundance of
specific (n,m) nanotubes in enriched samples. Furthermore, we presented experimental
evidence for ~50 meV exciton binding energy in metallic carbon nanotubes. In our nanotube
activities we collaborate closely with AG Thomsen.
78
From: H. Telg, C. Thomsen, and J. Maultzsch, Journal of Nanophotonics 4, 041660 (2010).
For graphene nanoribbons we studied symmetry and vibrational properties by ab-initio
calculations. We determined the symmetry properties of armchair and zigzag nanoribbons and
identified the Raman active modes, in particular the width-dependent breathing-like mode
(see figure). Our predictions have been recently confirmed on well-defined, chemically
synthesized nanoribbons.
From: R. Gillen, M. Mohr, and J. Maultzsch, Phys. Rev. B 81, 205426 (2010).
79
9.2b.3 Publications
1.
Longitudinal optical phonons in metallic and semiconducting carbon nanotubes
M. Fouquet, H. Telg, J. Maultzsch, Y. Wu, B. Chandra, J. Hone, T. F. Heinz, and
C. Thomsen
Phys. Rev. Lett., 102, 075501 (2009)
2.
Vibrational properties of graphene nanoribbons by first-principles calculations
Roland Gillen, Marcel Mohr, Christian Thomsen, Janina Maultzsch
Phys. Rev. B, 80, 155418 (2009)
3.
Two-dimensional electronic and vibrational band structure of uniaxially strained
graphene from ab initio calculations
M. Mohr, K. Papagelis, J. Maultzsch, C. Thomsen
Phys. Rev. B, 80, 205410 (2009)
4.
Kohn anomaly and electron-phonon interaction at the K-derived point of the
Brillouin zone of metallic nanotubes
P. Rafailov, J. Maultzsch, C. Thomsen, U. Dettlaff-Weglikowska, S. Roth
Nano Lett., 9, 3343-3348 (2009)
5.
Electronic properties of propylamine-functionalized single-walled carbon
nanotubes
M. Müller, R. Meinke, J. Maultzsch, Z. Syrgiannis, F. Hauke, A. Pekker, K. Kamaras,
A. Hirsch, C. Thomsen
submitted to ChemPhysChem (01/10)
6.
Symmetry based analysis of the Kohn anomaly and electron-phonon interaction in
graphene and carbon nanotubes
I. Milocevic, N. Kepcija, E. Dobardzic, M. Mohr, J. Maultzsch, C. Thomsen, M.
Damnjanovic
Phys. Rev. B, in print (2010)
7.
Electron-phonon coupling in grapheme
I. Milocevic, N. Kepcija, E. Dobardzic, M. Damnjanovic M. Mohr, J. Maultzsch, C.
Thomsen
Int. J. of Modern Physics B, 24, 655-660 (2010)
8.
Excitonic Rayleigh scattering spectra of metallic single-walled carbon nanotubes
Ermin Malic, Janina Maultzsch, Stephanie Reich, and Andreas Knorr
Phys. Rev. B 82, 115439 (2010).
9.
Observation of excitonic effects in metallic single-walled carbon nanotubes
P. May, H. Telg, G. Zhong, J. Robertson, C. Thomsen, and J. Maultzsch
Phys. Rev. B 82, 195412 (2010).
10.
Raman intensities of the radial-breathing mode in carbon nanotubes: the excitonphonon coupling as a function of (n1, n2)
H. Telg, C. Thomsen, and J. Maultzsch
Journal of Nanophotonics 4, 041660 (2010)
80
11.
Observation of Breathing-like Modes in an Individual Multiwalled Carbon
Nanotube
C. Spudat, M. Müller, L. Houben, J. Maultzsch, K. Goss, C. Thomsen, C. M. Schneider,
and C. Meyer
Nano Lett. 10, 4470 (2010)
12.
Excitonic absorption spectra of metallic single-walled carbon nanotubes
Ermin Malic, Janina Maultzsch, Stephanie Reich, and Andreas Knorr
Phys. Rev. B 82, 035433 (2010)
13.
Symmetry properties of vibrational modes in graphene nanoribbons
R. Gillen, M. Mohr, and J. Maultzsch
Phys. Rev. B 81, 205426 (2010)
14.
Time-resolved Raman spectroscopy of optical phonons in graphite: Phonon
anharmonic coupling and anomalous stiffening
H. Yan, D. Song, K.F. Mak, I. Chatzakis, J. Maultzsch, and T. F. Heinz
Phys. Rev. B 80, 121403(R) (2009)
9.2b.4 Invited Talks
J. Maultzsch
Vibrational properties of carbon nanotubes and graphene
nanoribbons
ACS (American Chemical Society) Meeting, Washington, DC,
August 16-20, 2009
J. Maultzsch
Vibrational properties of graphene nanoribbons
IWEPNM 2010, Kirchberg, Austria, March 6-13, 2010
81
9.2.c Department IIc
9.2c.1 Staff
Secretary
Ines Rudolph
Senior Scientists
Dr. Sebaz Reparaz
Dr. Markus Wagner
Dipl.-Phys. Miran Alic
Dipl.-Phys. Max Bügler
Dipl.-Phys. Munise Cobet (10.07.2010)
Dipl.-Phys. Ute Haboeck
Dipl.-Phys. Ronny Kirste
Dipl.-Phys. Martin Kaiser
Dipl.-Phys. Christian Kindel
Dipl.-Phys. Christian Nennstiel
Dipl.-Phys. Stefan Werner
Dipl.-Phys. Patrick Zimmer
Diploma Students (status of 31.12.2010: thesis completed = c)
Miran Alic (c)
Dorian Alden
Max Bügler (c)
Gordon Callsen
Ole Hitzemann (c)
Martin Kaiser ( c )
Thomas Kure
Thomas Switaiski
Stefan Mohn
82
Christian Nennstiel (c)
Christian Rauch (c)
Thomas Switaiski (c)
Jan-Henrik Schulze (c)
9.2c.2 Summary of Activities
The main research activities focus on the optical, vibronical and structural properties of II-VI
and III-V semiconductors with special emphasis on ZnO-, AlN-, InN- and GaN-based
structures. The investigations are carried out on single crystals, epitaxially grown homo- and
heterostructures, and especially low-dimensional structures like quantum wells,
nanowires, and quantum dots.
Excitonic complexes as a representative of the optical properties play an outstanding role in
the analysis of semiconductors. Excitonic excitation and relaxation mechanisms and the
dynamics of these processes are in the center of our interest which facilitates deep insight into
the physics of nitride- and oxide-based bulk and nanostructured material. Knowledge of the
energetic structure and relaxation mechanisms of free and bound excitons allows precise
analysis of defects created during e.g. growth, annealing, and doping procedures. Especially,
the analysis of extended structural defect centers in ZnO yielded novel insight based on
studies conducted in our research group. Fundamental distinctions in the optical signature of
extended structural defect centers allow their separation from common e.g. dopant-related
point defects.
All investigations are carried out in close cooperation with research groups aiming for the
development and optimization of e.g. new optoelectronic devices like blue light-emitting
diodes and lasers based on wide bandgap II-VI and III-V semiconductors. Cooperations have
been established with many research groups in Germany, Switzerland, Spain, France, Russia,
Belarus, Australia, China, UK, USA and Japan. The essential physical topics include:
exciton polaritons and bound excitons in bulk crystals and excitonic complexes in low
dimensional structures based on GaN, InN, AlN, InGaN, AlGaN, InGaAs and ZnO,
shallow and deep centers,
recombination dynamics and non-radiative processes,
non-linear optical effects of pure and doped wide bandgap semiconductors,
coherent dynamics,
analysis of doping and dopant compensation mechanisms,
functionalization of nanostructures,
cavity-like properties of nanowires, and
determination of deformation potentials.
83
The problem of p-dopant compensation and passivation in GaN-, AlGaN- and ZnO-based
structures attracts a lot of current attention. Intensive studies were dedicated to the behavior of
donor-acceptor pair emissions of highly p-doped ZnO- and GaN-layers. Furthermore, the
study of coherent processes especially with highly spatially localized excitation is a further
issue in our research. Coherent lifetimes react very sensitively to defect structures and can
thus help to optimize growth, annealing and doping techniques. Four-wave mixing techniques
could be applied to epitaxial layers of different II-VI compounds to receive non-linear
quantum beats. We have shown that they originate either from zero-field split excited states of
one complex or from interference between two different bound excitons.
The finalized construction of two either IR or UV optimized µTRPL setups facilitates
analysis and imaging of nanostructures with only diffraction limited spatial resolution. As a
result we were able to clearly resolve and analyze the spatial distribution of excitonic
lifetimes in e.g. cavity-like single ZnO nanowires which resulted several remarkable
publications. Additionally, the effect of functionalization of nanostructures with organic
molecules was studied with main focus on the occurring drastic excitonic lifetime changes.
Further future effords will be dedicated to the highly promising field of nanostructure
functionalization because of the outstandingly promising future applications in gas sensors,
catalytic processes and optoelectronics.
However, the µTRPL technique does not only allow such characterization of one-dimensional
structures, even quasi zero-dimenstional structures like individual quantum dots can be
analyzed. The purpose of the Sfb 787 project headed by Axel Hoffmann and Christian
Thomsen is to study the influence of the electron-phonon interaction in low-dimensional
semiconductor systems. Here, our main focus is the investigation of the dynamical properties
of excitonic states in II-VI and III-V quantum dots based on the µTRPL technique. The
collaboration with Yasuhiko Arakawa from the University of Tokyo resulted in a still ongoing
research exchange which originated several publications dealing with the characterization of
single GaN quantum dots. The large internal fields of such quantum dots make them an
outstanding candidate for future optoelectronic applications with main focus on secure and
efficient high speed data transmission.
In contrast to such directly application oriented characterization of e.g. quantum dots we also
participate in the determination of very fundamental material parameters like deformation
potentials. Especially the phonon deformation potentials in nitrides and ZnO have caught
our recent interest due to their lack or partly inconsistency in the literature. Raman
measurements under the application of hydrostatic as also uniaxial stress allowed us to clarify
and publish in the literature still missing and by the scientific community higly appreciated
values. Only the close international collaboration with Zlatko Sitar from the North Carolina
State University and Alejandro Goñi from the ICMAB realized the access to state of the art
material and for the high pressure measurements required equipment.
84
9.2c.3 Publications
1.
Bound and free excitons in ZnO: optical selection rules in the absence and
presence of time reversal symmetry
M.R. Wagner, H.W. Kunert, A.G.J. Machatine, A. Hoffmann, P. Niyongabo, J.
Malherbe, J. Barnas
Microelectronics Journal Volume 40, 289 (2009)
2.
Influence of substrate surface polarity on homoepitaxial growth of ZnO layers by
chemical vapour deposition
M. R. Wagner, T.P. Bartel, R. Kirste, A. Hoffmann, J. Sann, S. Lautenschläger, B. K.
Meyer, C. Kieselowski
Phys. Rev. B 79 (2009), 035307
3.
A systematic study on ZnO Materials containing group I materials (Li,Na,K)synthesis from precursors, characterization, and properties
S. Polarz, A. Orlov, A. Hoffmann, M.R. Wagner, C. Rauch, R. Kirste, W. Gelhoff, Y.
Aksu, M. Driess, M. W. van den Berg,M. Lehmann
Chem. Mat. 21 (2009), 3889
4.
Wave propagation of Rabi oscillations in one-dimensional quantum dot chain
G. Ya Slepyan, Y.D. Yerchak, S.A. Maksimenko, A. Hoffmann
Phys. Lett. A 373 (2009), 1374
5.
Matter coupling to strong electromagnetic fields in two-level quantum systems
with broken inversion symmetry
O.V. Kibis, G. Ya Slepyan, S.A. Maksimenko, A. Hoffmann
Phys. Rev. Lett. 102 (2009), 023601
6.
Magnetic and structural properties of transition metal doped zinc-oxide
nanostructures
A.O. Ankiewicz, W. Gehlhoff, J.S. Martins, A. S. Pereira, S. Pereira, A. Hoffmann,
E. M. Kaidashev, A. Rahm, M. Lorenz, M. Grundmann, M. C. Carmo, T. Trindade,
N. A. Sobolev
phys. stat. sol. (b) 246 (2009), 776
7.
Nitrogen incorporation in homoepitaxial ZnO CVD epilayers
S. Lautenschlaeger, S. Eisermann, B.K. Meyer, G. Callsen, M.R. Wagner, A. Hoffmann
phys. stat. sol. RRL, 3 (2009), 16-18
8.
Strong coupling of light with one-dimensional quantum dot chain from Rabi
oscillations to Rabi waves
G. Ya Slepyan, Y.D. Yerchak, S.A. Maksimenko, A. Hoffmann
Physics, Chemistry and Aplication of Nanostructures 3 (2009), 12071
9.
7 valence band symmetry related hole fine splitting of boundexcitons in ZnO
observed in magneto-optical studies
Markus R. Wagner, Jan- Hindrik Schulze, Ronny Kirste, Munise Cobet, Axel
Hoffmann, Christian Rauch, Anna V. Rodina, B.K. Meyer, Uwe Röder, Klaus Thonke
Phys. Rev. B 80 (2009), 205203
85
10.
Phonons and electronic states of ZnO, Al2O3 and Ge in the presence of time
reversal symmetry
A. G.J. Mechatine, H.W. Kunert, A. Hoffmann, J. Malherbe, J. Barnas, R. Seguin, M.R.
Wagner, P. Niyongabo, N. Nephale
Journal of Physics Conference Series 92 (2009), 12071
11.
EPR identification of intrinsic and transition metal-related defects in ZnGeP2 and
other II-IV-V2 compounds
W. Gehlhoff, A. Hoffmann
Physica B 404 (2009), 4942
12.
Light-matter coupling in nanostructures without an inversion center
O.V. Kibis, G. Ya Slepyan, S. A. Maksimenko, A. Hoffmann
Superlattice and Microstructures 47 (2010), 216
13.
Polariton effects in the dielectric function of ZnO excitons obtained by
ellipsometry
M. Cobet, C. Cobet, M.R. Wagner, N. Esser, C. Thomsen, A. Hoffmann
Applied Physics Letters 96 (2010), 031904
14.
Optical spectra of ZnO in the far UV: First Principle Calculations and
Ellipsometric measurements
Paola Gori, Munise Rakel, Christoph Cobet, Wolfgang Richter, Norbert Esser, Axel
Hoffmann, Rodolfo Del Sole, Antonio Cricenti, Olivia Pulci
Phys. Rev. B 81 (2010), 125207
15.
Size-dependent recombination dynamics in ZnO nanowires
J. S. Reparaz, F. Güell, M. R. Wagner, A. Hoffmann, A. Cornet, J. R. Morante,
Appl. Phys. Lett. 96 (2010), 053105
16.
Lithium related deep and shallow acceptors in Li- doped ZnO nanocrystals
C. Rauch, W. Gelhoff, M.R. Wagner, E. Malguth, G. Callsen, R. Kirste, B. Salameh,
A. Hoffmann, S. Polarz, Y. Aksu, M. Driess
J. Appl. Phys. 107 (2010), 024311
17.
Identification of a donor related recombination channel in ZnO thin films
Matthias Brandt, Holger von Wenckstern, Gabriele Benndorf, Martin Lange, Christof P.
Dietrich, Christian Kranert, Chris Sturm, Rüdiger Schmidt-Grund, Holger Hochmuth,
Michael Lorenz, Marius Grundmann, Markus R. Wagner, Miran Alic, Christian
Nenstiel, and Axel Hoffmann
Phys. Rev. B 81 (2010), 073306
18.
Theory of time-resolved Raman scattering and fluorescence emission from
semiconductor quantum dots
Julia Kabuß, Stefan Werner, Axel Hoffmann, Peter Hildebrandt, Andreas Knorr,
Marten Richter
Phys. Rev. B 81 (2010), 075314
86
19.
Growth temperature - phase stability relation in In1-xGaxN epilayers grown by
high-pressure CVD
G. Durkaya, M. Alevli, M. Buegler, R. Atalay, S. Gamage, M. Kaiser, R. Kirste, A.
Hoffmann, M. Jamil, I. Ferguson and N. Dietz
Mater. Res. Soc. Symp. Proc. Vol. 1202 © 2010
Materials Research Society 1202-I5.21-1
20.
Clebsch-Gordan coefficients for scattering tensors in ZnO
H. W. Kunert, M. R. Wagner, A. G. J. Machatine, P. Niyoganbo, J. Malherbe,
A. Hoffmann, J. Barnas, W. Florek
phys. stat. sol. (b) 247 (2010), 1802
21.
Strong electron-photon coupling in one-dimensional quantum dot chain:
Rabi waves and Rabi wavepackets
G. Ya. Slepyan, Y. D. Yerchak, A. Hoffmann, and F. G. Bass
Phys. Rev. B 81 (2010), 085115
22.
E-MRS 2009 Spring Meeting, Symposium J: Groupe III Nitride Semiconductors,
Strassburg, France, Proceedings, Guest editors: Olivier Briot, Axel Hoffmann,
Yasushi Nanishi, Fernando A. Ponce
phys. stat. sol (c) 7, (2010), Wiley-VCH
23.
Zinc Oxide- From fundamental properties towards novel application:
Influence of external fields
Markus R. Wagner and Axel Hoffmann
Chapter 8: Springer series in materials sciences 120 (2010), p 201
ed. Claus Franz Klingshirn, Bruno K. Meyer, Andreas Waag, Axel Hoffmann, Jean
Geurts
24.
Zinc Oxide- From fundamental properties towards novel application:
Deep centres in ZnO
Axel Hofmann, Enno Malguth and B.K. Meyer
Chapter 10: Springer series in materials sciences 120 (2010), p 233
ed. Claus Franz Klingshirn, Bruno K. Meyer, Andreas Waag, Axel Hoffmann, Jean
Geurts
25.
Recombination dynamics in ZnO nanowires: surface states vs. mode quality factor
J. S. Reparaz, F. Güell, M. R. Wagner, G. Callsen, R. Kirste, C. Claramunt,
J. R. Morante, and A. Hoffmann
Appl. Phys. Lett. 97 (2010), 133116
26.
Spectral identification of impurities and native defects in ZnO
B.K. Meyer, D.M. Meyer, J. Stehr, A. Hoffmann
Wiley-VCH Buch über ZnO ed. C. Litton (2010)
27.
Reduction of the transverse effective charge of optical phonons in ZnO under
pressure
J.S. Reparaz, L. R. Muniz, M. R. Wagner, A. R. Goni, M. I. Alonso, A. Hoffmann,
B.K. Meyer
App. Phys. Lett. 96 (2010), 231906
87
28.
Exciton fine-structure splitting in GaN/AlN quantum dots
C. Kindel, S. Kako, T. Kawano, H. Oiishi, Y. Arakawa, G. Hönig, M. Winkelnkemper,
A. Schliwa, A. Hoffmann, D. Bimberg
Physical Review B 81 (2010), 241309 (R)
29.
Molecular precursor route to a metastable from of zinc oxide
Carlos Lizandara Pueyo, Stephan Siroky, Steve Landsmann, Maurits W. E. van den
Berg, Markus R. Wagner, Juan S. Reparaz, Axel Hoffmann, Sebastian Polarz
Chem. Mater. 22 (2010), 4263
30.
Optical properties of InN grown on templates with controlled surface polarities
Ronny Kirste, Markus R. Wagner, Jan H. Schulze, Andre Strittmatter, Ramon Colazzo,
Zlatko Sitar, Mustafa Alevli, Nikolaus Dietz, Axel Hoffmann
phys.stat sol. (a) 207 (2010), 2351
31.
Large internal dipole moment in InGaN/GaN quantum dots
Irina A. Ostapenko, Gerald Hönig, Christian Kindel, Sven Rodt, Andre Strittmatter,
Axel Hoffmann, Dieter Bimberg
Appl. Phys. Lett. 97 (2010), 063103
32.
The influence of group V/III molar precursor ratio on the structural properties of
InGaN layers grown by HPCVD
G. Durkaya, M. Buegler, R. Atalay, I. Senevirathna, M. Alevli, O. Hitzemann, M.
Kaiser, R. Kirste, A. Hoffmann, N. Dietz
phys. stat. sol. (a) 207 (2010), 1379
33.
Reactor pressure: growth temperature relation for InN epilayers grown by highpressure CVD
M. Buegler, S. Gamage, R. Atalay, J. Wang, I. Senevirathna, R. Kirste, T. Xu, M. Jamil,
I. Ferguson, J. Tweedie, R. Collazo, A. Hoffmann, Z. Sitar, N. Dietz
Proc. SPIE 7784 (2010), 77840F
34.
Excited state properties of donor bound excitons in ZnO
Bruno. K. Meyer, Joachim Sann, Sebastian Eisermann, Stefan Lautenschlaeger,
Markus R. Wagner, Martin Kaiser, Gordon Callsen, Juan S. Reparaz A. Hoffmann
Phys. Rev. B 82 (2010), 115207
35.
Shape anisotropy influencing functional properties: trigonal prismatic ZnO
nanoparticals as an example
Carlos Lizandara Pueyo, Stephan Siroky, Markus R. Wagner, Axel Hoffmann, Juan S.
Reparaz, Michael Lehmann, Sebastian Polarz
Advance Functional Materials 21 (2011), 295
36.
Raman and photoluminescence spectroscopic detection of surface-bound Li+O2defect sites in Li-doped ZnO nanocrystals derived from molecular precursors
Ronny Kirste, Yilmaz Aksu, Markus R. Wagner, Sevak Khachadorian, Surajit Jana,
Matthias Driess, Christian Thomsen, Axel Hoffmann
Chem. Phys. Chem. 12 (2011), 1189
88
37.
Determination of phonon deformation potentials in wurtzite GaN and ZnO by
uniaxial pressure dependent Raman measurements
G. Callsen, J. S. Reparaz, M. R. Wagner, R. Kirste, C. Nenstiel, A. Hoffmann, and M.
R. Phillips
Appl. Phys. Lett. 98 (2011), 061906
38.
Acoustic and optical phonon scattering in a single In(Ga)As quantum dot
Erik Stock, Matthias-Rene Dachner, Till Warming, Andrei Schliwa, Anatol Lochmann,
Axel Hoffmann, Aleksandr I. Toropov, Askhat K. Kakarov, Ilya A. Derebzov, Marten
Richter, Vladimir A. Haisler, Andreas Knorr, Dieter Bimberg,
Phys. Rev. B 83 (2011), 041304(R)
39.
Comment on the paper pss (a) 205, 1872: Paramagnetic and ferromagnetic
resonance studies on dilute magnetic semiconductors on GaN
W. Gehlhoff, B. Salameh, A. Hoffmann
phys. stat. sol. (a) 207 (2011), 1379
89
9.2c.4 Invited Talks
Axel Hoffmann
Spatially and time resolved spectroscopy of excitons and
phonons in low dimensional semiconductors
School of Nanostructures, Santiago de Cuba, January 2009
Axel Hoffmann
Optical and vibrational properties of high quality ZnO
substrates under uniaxial pressure
SPIE Photonic West 2009, San Jose, USA, January 2009
Axel Hoffmann
Single dot spectroscopy- nitrides vs. arsenides
PLMNC 9 Lecce, Italy, April 2009
Axel Hoffmann
substrates
MRS Fall Meeting 2010, Boston, USA, December 2009
Axel Hoffmann
Radiative and nonradative decay in group III nitrides
SPIE 2010, San Francisco, USA, January 2010
Axel Hoffmann
Radiative and nonradative decay in group III nitrides
Sinople 2010, Berlin, Germany, March 2010
Axel Hoffmann
InAs- and GaN- quantum dots: Similarities and differences
CIMTEC 2010, Montecantini Terme, Italy, June 2010
Axel Hoffmann
Towards real-world quantum communication: Quantum
dots as non-classical light sources
ISGN3, Montpellier, France, July 2010
Axel Hoffmann
substrates
Int. Workshop of ZnO 2010, Changchun, China, August 2010
Axel Hoffmann
Quantum dots as non-classical light sources: The interplay
between polarization effects and electron-hole exchange
INOW 2010, Changchun, China, August 2010
Axel Hoffmann
Case study of successful Australian–European
collaborations
BMBF workshop, Bonn, Germany, November 2010
90
9.2b.5 Diploma Theses
Miran Alic
Zeitaufgelöste Untersuchungen an niederdimensionalen III-V
Halbleitern
21.12.2009
Gordon Callsen
Optische Eigenschaften von niederdimensionaln
Halbleiterstrukturen
23.06.2009
Ole Hitzemann
Untersuchungen an verdünnten magnetischen Halbleitern als
Materialien für die Spintronik
25.05.2010
Martin Kaiser
Optische Eigenschaften tiefer Zentren in Breitbandhalbleitern
26.02.2010
Christian Nenstiel
Lumineszenz und Hochanregungsmechanismen in Gruppe-III
Nitriden
20.07.2009
Jan-Hindrik Schulze
Dynamische Eigenschaften von Breitband-Halbleitern in äußeren
Feldern
29.05.2009
Thomas Switaiski
Mikrophotolumineszenzuntersuchungen an Quantenpunkten
06.07.2009
91
9.3
Department III
9.3.1 Staff
Secretary
Angela Berner (part time)
Technical Staff
Gerhard Pruskil
Senior Scientists
Dr. Holger Eisele
Dr. Lena Ivanova (until 06.06.2010)
Dr. Andrea Lenz
Dr. Rainer Timm (until 31.01.2009)
PhD Candidates (status of 31.12.2010 - thesis completed = c)
Dipl.-Phys. Martin Franz
Dipl.-Phys. Jan Grabowski (c)
Dipl.-Phys. Kai Hodeck (c)
Dipl.-Phys. Lena Ivanova (c)
Dipl.-Phys. Christopher Prohl
Diploma and Master Students (status of 31.12.2010 – thesis completed = c)
Stephan Appelfeller
Martin Franz (c)
Florian Genz (c)
Britta Höpfner (c)
Nadine Oswald (c)
Christopher Prohl (c)
Matthias Vetterlein (c)
92
The main research subject of the group of Mario Dähne is the investigation of the structural
and (local) electronical properties of semiconductor surfaces, interfaces, and nanostructures.
In the experiments, special emphasis lies on the use of local probes, such as scanningtunneling microscopy (STM) and spectroscopy (STS) and – for studies of buried structures –
cross-sectional scanning-tunneling microscopy (XSTM) and spectroscopy (XSTS).
Complementary information on the electronic band structure is obtained from angle-resolved
photoelectron spectroscopy (ARPES) with synchrotron radiation at the Berlin storage ring
BESSY. All experiments are performed in ultra-high vacuum (UHV).
There are three experimental setups:
1. An STM chamber with a preparation chamber containing LEED, sputter gun and effusion
cells
2. A chamber designed especially for XSTM experiments
3. A III-V MBE chamber with in-situ STM analysis, provided by Prof. Jacobi from the FritzHaber-Institut
For ARPES experiments, chambers provided by cooperation partners are used.
The most important recent results are given in the following:
1. Silicide thin films, nanowires, and clusters
Using STM and ARPES, the formation and properties of lanthanide silicide nanostructures on
Si surfaces were investigated in detail [3,6,16]. Both two-dimensional and one-dimensional
electronic properties could be found for silicide nanowires. Using a display-type toroidal
electron spectrometer developed by LaTrobe University in Bundoora, Australia, we were able
to map the two-dimensional energy surfaces. Here a very similar two-dimensional dispersion
was found both for silicide thin films on Si(111) and for nanowires on Si(557) [6,14], which
could be related to hexagonal disilicide monolayers. The figure shows the structure of the
nanowires on Si(557) and their Fermi surface.
Currently, the formation, structure, and electronic properties of silicide clusters grown on Si
surfaces are studied.
2. Initial stages of InAs quantum-dot growth
In the MBE-STM chamber, the atomic structure of the evolving InAs wetting layer on the
GaAs(001)-c(4×4) surface was studied up to quantum-dot formation [8,11,15]. The wetting
layer was found to develop in a three-stage process, starting with In agglomerations, which
transform at about 0.67 ML into a (4×3) reconstructed In2/3Ga1/3As monolayer, as shown in
93
the figure. Further on, the In2/3Ga1/3As monolayer is covered by a (2×4) reconstructed InAs
film. After 1.42 ML InAs exposure, the critical thickness for quantum-dot formation is
reached.
3. Atomic structure of InAs/GaAs submonolayer nanostructures
Using XSTM the atomic structure of submonolayer InAs nanostructures embedded in GaAs
was studied [18]. The samples were grown in Department I using MOCVD. Rather small
structures with very high densities in the 1012/cm2 range were observed. A strong vertical
segregation with segregation lengths around 1 nm was found. The figure shows the XSTM
image of a stack with 5 layers each containing 0.5 ML InAs separated by 16 layers of GaAs
together with the variation of the local lattice constant and therewith of the local
stoichiometry, allowing a quantitative analysis of the segregation. In the case of thin GaAs
spacer layers, this leads to vertically coherent InGaAs structures instead of the nominally
assumed InAs/GaAs stacks.
4. Formation of InAs quantum dashes in InGaAsP
In a cooperation with the Heinrich-Hertz-Institut, using XSTM we studied InAs embedded
within InGaAsP layers lattice matched on InP bulk material. Here we observed zero-dimensional nanostructures strongly elongated along [110] direction, so-called quantum dashes
[7,13]. This observation is in contrast to the InAs/GaAs system, where smaller quantum dots
are formed, exhibiting a rather 4-fold structural symmetry. The figure shows cross-sectional
images of the InAs/InGaAsP/InP(001) quantum dashes taken at both perpendicular cleavage
planes. The quantum dashes, marked by ellipses, have an almost binary InAs composition and
94
a truncated pyramidal shape. Their lengths and widths were found to lie around 60 nm and
15 nm, respectively, resulting in lateral aspect ratios around 4. The quaternary matrix material
surrounding the dashes is characterized by a lateral decomposition resulting in InAs-rich and
GaP-rich columns, which are correlated with the positions of the quantum dashes, as marked
by the dashed lines.
5. Influence of nitrogen on the properties of arsenide nanostructures
In cooperation with the Paul-Drude-Institut and the Tyndall Institute in Cork, Ireland, the socalled diluted nitrides were studied [12,17]. Using XSTM it was found that nitrogen exposure
during InAs quantum-dot growth leads to a strong dilution by Ga from the capping layer of
otherwise compact InAs quantum dots. The figure shows InAs quantum dots grown without
(left) and with (right) nitrogen exposure. It is observed that the indium even segregates into
the substrate upon nitrogen exposure. Furthermore, the density of states of diluted GaAsN
was measured using XSTS. Here the influence of nitrogen on the GaAs conduction band
states could be studied in detail. It could be shown that the second band gap predicted by the
so-called BAC model does not exist, but there is an energy interval of reduced DOS, which
could be modelled well by an advanced theoretical approach contributed by the group from
the Tyndall Institute in Cork.
6. Electronic structure of GaSb quantum rings embedded in GaAs
The structural and local electronic properties of GaSb nanostructures on GaAs(001) were
studied in a cooperation with the University of Cambridge, UK, and the Carnegie Mellon
University in Pittsburgh, USA [5,19]. As shown in the XSTM image in the figure, here
mostly GaSb ring structures are observed, which are filled by almost pure GaAs, in contrast to
the more compact InAs/GaAs quantum dots. The GaSb quantum rings revealed a type-II band
95
offset typical for the GaSb/GaAs system, as shown in the XSTS spectra in the figure.
Furthermore, the contrast in XSTM images at type-II systems was studied in detail involving
the effects of tip-induced band bending.
7. Structure and electronic properties of non-polar GaN surfaces
Using XSTM and XSTS, we studied the atomic structure and electronic properties of the nonpolar GaN(1010) cleavage surface [1,4,9,14] in cooperation with the Forschungszentrum
Jülich and with Osram Opto-Semiconductors GmbH. We were able to achieve atomic
resolution on the GaN(1010) surface and found that the surface is unreconstructed. As shown
on the left side of the figure there are no intrinsic surface states within the fundamental band
gap. Furthermore we found different dislocation types and could derive their burgers vectors,
line directions, and charge states. An example for an uncharged perfect screw dislocation is
shown on the right side of the figure. In addition, we could observe a modulation of the Si
doping concentration during growth along the [0001] direction.
8. Electronic Structure of the InN(1120) surface
Using XSTS we studied the (1120) surface of monocrystalline InN [Appl. Phys. Lett. 98,
062103 (2011)], in collaboration with both the Forschungszentrum Jülich and the National
Tsing Hua University, Taiwan. We could derive a band gap of 0.7 eV for InN using only
direct electronic measurements. Moreover, it could be shown that the assumed generality of
an electron accumulation on InN surfaces is absent in the case of stoichiometric non-polar
surfaces. In this case, the Fermi level is found within the fundmental band gap, indicating that
the electron accumulation is not an intrinsic property of InN, but can be assigned to
decomposition and/or adsorbance of molecules from the air. Furthermore, it could be shown
that the fundamental bulk band gap is free of intrinsic surface states at the (1120) surface.
96
9.3.3 Publications
1. Electronic properties of dislocations in GaN investigated by scanning tunneling
microscopy,
Ph. Ebert, L. Ivanova, S. Borisova, H. Eisele, A. Laubsch, and M. Dähne,
Appl. Phys. Lett. 94, 062104 (2009).
2. Limits of In(Ga)As/GaAs quantum dot growth,
A. Lenz, H. Eisele, R. Timm, L. Ivanova, R.L. Sellin, H.-Y. Liu, M. Hopkinson, U.W.
Pohl, D. Bimberg, and M. Dähne,
Phys. Stat. Sol. (b) 246, 717 (2009).
3. Structural and electronic properties of rare-earth silicide nanowires on Si(557),
M. Wanke, K. Löser, G. Pruskil, and M. Dähne,
Phys. Rev. B 79, 155428 (2009).
4. Doping modulation in GaN imaged by cross-sectional scanning tunneling
microscopy,
H. Eisele, L. Ivanova, S. Borisova, M. Dähne, M. Winkelnkemper, and Ph. Ebert,
Appl. Phys. Lett. 94, 162110 (2009).
5. Contrast mechanisms in cross-sectional scanning tunneling microscopy of
GaSb/GaAs type-II nanostructures,
R. Timm, R.M. Feenstra, H. Eisele, A. Lenz, L. Ivanova, E. Lenz, and M. Dähne,
J. Appl. Phys. 105, 093718 (2009).
6. Energy surfaces of rare-earth silicide films on Si(111),
M. Wanke, M. Franz, M. Vetterlein, G. Pruskil, B. Höpfner, C. Prohl, I. Engelhardt, P.
Stojanov, E. Huwald, J. Riley, and M. Dähne,
Surf. Sci. 603, 2808 (2009).
7. Formation of InAs/InGaAsP quantum dashes on InP(001),
A. Lenz, F. Genz, H. Eisele, L. Ivanova, R. Timm, D. Franke, H. Künzel, U.W. Pohl, and
M. Dähne,
Appl. Phys. Lett. 95, 203105 (2009).
8. Evolution of the InAs wetting layer on GaAs(001)c(4x4) on the atomic scale,
J. Grabowski, C. Prohl, B. Höpfner, M. Dähne, and H. Eisele, Appl. Phys. Lett. 95,
233118 (2009).
9. Scanning tunneling microscopy on unpinned GaN(1100) surfaces: Invisibility of
valence-band states,
Ph. Ebert, L. Ivanova, and H. Eisele,
Phys. Rev. B 80, 085316 (2009).
10. Adsorbate-induced restructuring of Pb mesas grown on vicinal Si(111) in the
quantum regime,
A.A. Khajetoorians, W. Zhu, J. Kim, S. Qin, H. Eisele, Z. Zhang, and C.-K. Shih,
Phys. Rev. B 80, 245426 (2009).
97
11. Atomic structure of the (4x3) reconstructed InGaAs monolayer on GaAs(001),
H. Eisele, B. Höpfner, C. Prohl, J. Grabowski, and M. Dähne,
Surf. Sci. 604, 283 (2010).
12. Effect of nitrogen on the InAs/GaAs quantum dot formation,
L. Ivanova, H. Eisele, A. Lenz, R. Timm, O. Schumann, L. Geelhaar, H. Riechert, and M.
Dähne,
Phys. Stat. Sol. (c) 7, 355 (2010).
13. InAs nanostructures on InGaAsP/InP(001): Interaction of InAs quantum dash
formation with InGaAsP decomposition,
F. Genz, A. Lenz, H. Eisele, L. Ivanova, R. Timm, U.W. Pohl, M. Dähne, D. Franke, and
H. Künzel,
J. Vac. Sci. Technol. B 28, C5E1 (2010).
14. Cross-sectional scanning tunneling microscopy and spectroscopy of non-polar
GaN(1100) surfaces,
H. Eisele, S. Borisova, L. Ivanova, M. Dähne, and Ph. Ebert,
J. Vac. Sci. Technol. B 28, C5G11 (2010).
15. Atomic structure and strain of the InAs wetting layer growing on GaAs(001),
C. Prohl, B. Höpfner, J. Grabowski, M. Dähne, and H. Eisele,
J. Vac. Sci. Technol. B 28, C5E13 (2010).
16. Electronic properties of dysprosium silicide nanowires on Si(557),
M. Wanke, M. Franz, M. Vetterlein, G. Pruskil, C. Prohl, B. Höpfner, P. Stojanov, E.
Huwald, J. Riley, and M. Dähne,
J. Appl. Phys. 108, 064304 (2010).
17. Direct measurement and analysis of the conduction band density of states in diluted
GaAs1-xNx alloys,
L. Ivanova, H. Eisele, M.P. Vaughan, Ph. Ebert, A. Lenz, R. Timm, O. Schumann, L.
Geelhaar, M. Dähne, S. Fahy, H. Riechert, and E.P. O’Reilly,
Phys. Rev. B 82, 161201(R) (2010).
18. Atomic structure of buried InAs sub-monolayer depositions in GaAs,
A. Lenz, H. Eisele, J. Becker, L. Ivanova, E. Lenz, F. Luckert, K. Pötschke, A.
Strittmatter, U.W. Pohl, D. Bimberg, and M. Dähne,
Appl. Phys. Express 3, 105602 (2010).
19. Confined states of individual type-II GaSb/GaAs quantum rings studied by crosssectional scanning tunneling spectroscopy,
R. Timm, H. Eisele, A. Lenz, L. Ivanova, V. Vossebürger, T. Warming, D. Bimberg, I.
Farrer, D.A. Ritchie, and M. Dähne,
Nano Lett. 10, 3972 (2010).
98
9.3.4 Invited Talks
M. Dähne
Rare earth silicide nanowires on silicon surfaces
DPG Frühjahrstagung, Regensburg, 21.-26. March 2010
H. Eisele
Scanning Tunneling Microscopy for Semiconductor Analysis,
Solid state physics colloquium, Tyndall National Institute, Cork,
Ireland, February 2009
H. Eisele
The 2D-3D and Quantum Dot-Quantum Ring Phase Transitions
during Growth of InAs/GaAs and GaSb/GaAs Nanostructures
International Conference on the Formation of Semiconductor
Interfaces, Weimar, July 2009
H. Eisele
Material deposition and reorganization during growth and
capping of GaAs-based nanostructures
SemicoNano 2009, Anan, Japan, August 2009
H. Eisele
Cross-sectional scanning tunnelling microscopy of non-polar GaN
surfaces
Abschlusskolloquium, DFG-Schwerpunkt Nitride, Universität
Bremen, October 2009
H. Eisele
XSTM and XSTS for the analysis of semiconductor
nanostructures
Festkörperkolloquium, Universität Marburg, December 2009
H. Eisele
Cross-sectional scanning tunneling microscopy study of non-polar
GaN(1100) surfaces
International Workshop on Nitride Semiconductors, Tampa/FL,
19. – 23. Sep. 2010
H. Eisele
Cross-sectional scanning tunneling microscopy of pure and
diluted nitride semiconductors
18th International Vacuum Congress, Beijing, 23. – 27. Aug. 2010.
H. Eisele
Semiconductor nano-structure analysis with scanning tunneling
microscopy
Paul-Drude-Institute, Berlin, 21. Jun. 2010
H. Eisele
Nanostructure analysis using STM
Blockseminar 2010 of the Graduiertenkolleg of the Sfb 787, TU
Berlin, Graal-Müritz, 9. – 11. May 2010.
H. Eisele
Cross-sectional STM and plane-view STM for the
characterization of III-V semiconductor nanostructures
University of California at Los Angeles, Los Angeles/CA, 1. Feb.
2010.
99
H. Eisele
Nature of surface states and dislocations on non-polar GaN(1100)
surfaces investigated by scanning tunneling microscopy
Palo Alto Research Center, Palo Alto/CA, 28. Jan. 2010
H. Eisele
Cross-sectional scanning tunneling microscopy of non-polar GaN
surfaces
Department of Physics, Carnegie-Mellon-University, Pittsburgh/PA,
19. Jan. 2010
H. Eisele
Cross-sectional scanning tunneling microscopy of non-polar GaN
surfaces
Center of High Technology Materials, University of New Mexico,
Albuquerque/NM, 15. Jan. 2010.
H.-E. Gumlich
Moderne Physiker: Ihre Haltung zum Glauben an Gott,
Lehrerfortbildung für Ethik-Lehrer, Martin-Luther-Universität HalleWittenberg, June 2009
L. Ivanova
Characterization of GaAsN Quantum Wells, GaInNAs by
Scanning Tunneling Microscopy
Solid state physics colloquium, Ohio University, Athens, USA,
November 2009
L. Ivanova
Structural and Electronic Properties of non-polar GaN(1-100)
Surfaces
Solid State physics colloquium, University of Michigan, Ann Arbor,
USA, November 2009
L. Ivanova
GaAsN/GaAs Semiconductors Studied by Scanning Tunneling
Microscopy
Festkörperkolloquium, Universität Marburg, December 2009
A. Lenz
Structural investigation on III-V semiconductor heterostructures
and magic clusters on Si(111)(7x7)
Solid state physics colloquium, LaTrobe University, Bundoora,
Australia, August 2009
100
Martin Franz
Atomare Struktur von Silizid-Nanodrähten
30.01.2009
Florian Genz
Atomare Struktur von phoshpidbasierten
Halbleiternanostrukturen
21.07.2009
Britta Höpfner
Strukturelle Eigenschaften des InAs/GaAs-Systems vor und nach
der Quantenpunktentstehung
08.03.2009
Nadine Oswald
Atomare Struktur von stickstoffhaltigen III-V-Halbleiternanostrukturen
07.12.2009
Christopher Prohl
Strukturelle Eigenschaften von Submonolagen-Bedeckungen im
InAs/GaAs-Quantenpunktsystem
06.03.2009
Matthias Vetterlein
Überwachsen von Silizid-Nanodrähten mit Silizium
09.03.2009
101
9.4
Department IV
Prof. Dr. rer. nat. Wolfgang Richter (retired)
9.4.1 Staff
Secretary
Claudia Hinrichs
Technical Staff
Matthias Dreier
Engelbert Eder
Senior Scientists
Dr. Markus Pristovsek
Dr. Patrick Vogt
Dr. Tim Wernicke
Dr. Abdul Kadir
PhD Candidates (status of 31.12.2010 – thesis completed = c)
Dipl.-Phys. Konrad Bellmann
Dipl.-Phys. Thomas Bruhn
Dipl.-Phys. Ralph Debusmann
Dipl.-Phys. Duc Dinh
Dipl.-Phys. Marcel Ewald
Dipl.-Phys. Martin Frentrup
Dipl.-Phys. Christian Friedrich
Dipl.-Phys. Tim Kolbe
Dipl.-Phys. Raimund Kremzow (c), until 30.11.2010
Dipl.-Phys. Martin Leyer
M. Sc. Neysha Lobo
Dipl.-Phys. Martin Martens
Dipl.-Phys. Christian Meißner
Dipl.-Phys. Simon Ploch
Dipl.-Phys. Jens Raß
Dipl.-Phys. Luca Redaelli
Dipl.-Phys. Jessica Schlegel
Dipl.-Phys. Daria Skuridina
Dipl.-Phys. Joachim Stellmach
Dipl.-Phys. Jan-Robert Van Look
102
Diploma, Master and Bachelor Students (status of 31.12.2010 – thesis completed = c)
Eric Bauch (c)
Amelie Biermann (c)
Fabian Budack
Florian Duge
Johannes Falkenburg
Martin Frentrup (c)
Martin Guttmann, B.Sc. (c.)
Marc Hoffmann (c)
Michael Högele (c)
Michael Hoppe (c)
André Kruse (c)
Gunnar Kusch
Igor Kuznecov (c)
Martin Martens (c)
Frank Mehnke
Christoph Reich
Linda Riele (c)
Marc-Antonius Rothe
Özgür Savas (c)
Julia Schmermbeck, M.Sc.
Matthias Schmies (c)
Tilman Schwaner
Katrin Sedlmeier (c)
Toni Sembdner (c)
Sergej Solopow
Marcus Stascheit
Christian Ulbrich, B.Sc. (c)
Alexander Wolf, B.Sc. (c)
103
The “Experimental Nanophysics and Photonics” group is exploring a wide range of topics
including metalorganic vapor phase epitaxy (MOVPE) of group III-nitride compounds and
nanostructures, the study of optical and electronic properties of semiconductor surfaces and
interfaces, and the development of novel optoelectronic devices. The material system AlNGaN-InN covers an extraordinarily wide wavelength range, that includes the entire visible
spectrum and ranges from the deep ultraviolet (UV) to the near infrared. This exceptional
versatility makes InAlGaN heterostructures exceedingly interesting for numerous new device
applications. These include near and deep ultraviolet (UV) InAlGaN light emitting diodes
(LEDs), high power and high brilliance blue-green laser diodes, GaN-based semiconductor
disk lasers (SCDL), vertical cavity surface emitting lasers (VCSELs) and single photon
emitter (SPE). These new devices are key enabler for numerous applications, including e.g.
the purification of drinking water, phototherapy, medical diagnostics, laser projection
displays, and quantum cryptography. The research activities in the “Experimental
Nanophysics and Photonics” group are conducted in close collaboration with the GaN
Optoelectronics Business Area at the Ferdinand-Braun-Institut, Leibniz Institut für
Höchstfrequenztechnik (FBH) located on the Science and Technology Campus in BerlinAdlershof. By combining competencies in both basic and applied research, our goal is to
establish a European centre of excellence in the field of nitride materials growth and devices.
The research activities are being supported by a number of research grants. This includes the
project “Materials for high brilliance green laser diodes” which is funded by the German
Research Foundation (DFG) as part of the Collaborative Research Centre (SFB 787)
“Semiconductor Nanophotonics”. In addition, the development of InGaN quantum well
laser heterostructures on semipolar growth surfaces is supported within the DFG research
group “Polarisation field control in nitride light emitters” (FOR 957). We have also
obtained a number of individual grants from the German Research Foundation (DFG). These
include the development of GaN-based semiconductor disk lasers (SCDL) for emission in the
blue-violet wavelength range, the investigation of nanostructure growth during metalorganic
vapour phase epitaxy by in-situ scanning tunnelling microscopy, and the investigation of
atomic structure of InGaN surfaces. Funded by the German Federal Ministry of Education and
Research (BMBF) the joint research project „Deep UV LEDs“ was established, which
targets the development of highly efficient light emitting diodes in the UVB and UVC
spectral range. In July 2009 a new BMBF funded regional growth core “Berlin WideBaSe”
was launched. The research activities within Berlin WideBaSe are focused on the
development, manufacturing and distribution of wide bandgap semiconductor optoelectronic
and electronic devices. Berlin WideBaSe combines the know-how and technical resources of
ten small and medium size companies as well as three research institutes in Berlin. In the
context of the European Union the “RAINBOW” Initial Training Network (ITN) has been
established with the goal to develop high quality InN layers and heterostructures for
applications in solar cells and high frequency electronics. In addition the new EU STREP
project “FemtoBlue” has been launched in September 2009 to develop short-pulse multisection blue laser diodes.
The activities of the Experimental Nanophysics and Photonics Group are organized in three
closely coupled research areas with complementary objectives:
-
metalorganic vapour phase epitaxy of nitride based nano- and heterostructures
-
the development of novel nanophotonic devices
-
the characterization of surfaces and interfaces
104
Epitaxy of nitride based materials and nanostructures
A major step in advancing our growth capability was the establishment of a new 3x2”
Thomas Swan Close-Coupled Showerhead MOVPE reactor for the growth of III-nitride
heterostructures, which complements our existing single wafer Epigress and Aixtron MOVPE
systems. One of our goals in the area of epitaxy is to obtain a better understanding of the
fundamental growth processes in MOVPE by using in-situ characterization techniques like
spectroscopic ellipsometry, reflectometry and wafer curvature measurements. A fundamental
challenge for the growth of nitride semiconductor alloys InGaN and AlGaN is the large strain
at heterointerfaces due to the lattice mismatch. Apart from the limits imposed by strain, e.g.
the formation of misfit dislocation or 3D growth, strain also effects the efficiency of light
emitting devices, e.g. due to the quantum-confined Stark effect (QCSE). To accommodate
strain in AlGaN layers grown on AlN/sapphire templates for LEDs emitting in the UV region,
we have successfully developed short period superlattice structures. The superlattice structure
enables crack-free growth in the entire composition range, giving a largely relaxed AlGaN
template for devices. Such AlGaN templates also exhibit significantly reduced threading
dislocation densities in comparison to AlN templates and offer the possibility for strain
engineering. In the InGaN system we determined the critical thickness for relaxation and 2D
to 3D transition on GaN templates and the effects on surface structure, alloy composition and
defect density. The strain can be used by the formation of Quantum dots due to the strain
induced Stranski-Krastanov growth mode. Furthermore such quantum dots can be used for
single photon emitter as well as for lasers. We demonstrated control of quantum dot size and
density over 2 orders of magnitude. Another novel approach is the growth of AlGaN and
InGaN in so called semi- or nonpolar crystal orientations. These orientations are tilted with
respect to the [0001] direction. Therefore, quantum wells on such crystal planes exhibit
reduced polarization fields. First suitable substrates and growth parameters of the binary
alloys InN, GaN and AlN needed to be established. Additionally, the use of foreign substrates
can lead to the formation of domains with different crystal orientation. We demonstrated the
growth of single phase semipolar InN, GaN and AlN as well as AlGaN in the whole
composition range. Furthermore basic properties that define the growth are studied. They are
very different to the (0001) surface. Desorption and adatom mobilities are anisotropic and
depend strongly on the surface orientation.
700
320mA 500ms
511nm
Intensity (counts)
600
500
400
300
200
100
350
400
450
500
550
600
650
emission wavelength (nm)
Pulsed electroluminescense of a threefold
InGaN/GaN quantum well just below 3D
transition (23% 2.5 nm).
2µm x 2µm Atomic Force Microscopy of
low density InGaN quantum dots with an
indium content of about 23 %.
105
Nitride bases devices: From UV LEDs to blue-green lasers
The research profile of the group includes a strong emphasis on nanophotonic devices based
on III-nitride wide bandgap semiconductors. The activities include the development
technology base for the growth and fabrication of light emitting diodes (LEDs) and laser
diodes (LDs) as well as developing concepts for next generation short wavelength light
sources. A new field of devices, solarblind UV photodetectors, is also currently studied
utilizing epitaxy, device fabrication, characterization and simulation. The growth and
fabrication processes of LED devices were successfully established as demonstrated by LEDs
in the emitting in the green spectral range near 500 nm down to deep UVB LEDs emitting at
320 nm and first devices emitting below 300 nm. More complex and challenging growth and
fabrication processes for LDs were also successfully established as demonstrated by 405 nm
current-injection ridge-waveguide LDs under cw operation, current-injection LDs under
pulsed operation from 400 nm to 435 nm as well as optically pumped laser structures from
326 nm to 470 nm. This technology base and the establishment of into state-of-the art devices
build the foundation for the development of novel concepts for LEDs and LDs.
Photographic images of semipolar (20-21) InGaN MQW LED chips
emitting at 430 nm (left) and 500 nm (right).
The novel concepts that are under investigation aim for the extension of the wavelength range
of LEDs and LDs as well as improving the efficiency and open up new applications. New
applications are targeted by the development of multi-section laser diodes for ps-pulse
generation. Also the development of semiconductor disk lasers opens up new applications due
to the high pulse peak power and the high beam quality as well as the scalability and the
possibility to include nonlinear optical element into the cavity. Semiconductor disk lasers
with peak pulse output power of more than 300 W and an emission wavelength of 393 nm
have been demonstrated. Meanwhile first semiconductor disk lasers with an emission
wavelength of 420 nm have also been realized. In order to push the lasing wavelength towards
the green spectral region, the growth of quantum dot active regions is studied. Also the bluegreen wavelength region is targeted by lasers on non- and semipolar growth facets. Such
structures suffer less from the quantum-confined Stark effect enabling higher material gain.
Hereby the studies also revealed different incorporation efficiencies of indium into the active
region allowing for more favourable growth conditions of long wavelength active regions. On
the short wavelength side deep UV LEDs in the UV-B and UV-C range are studied. Epitaxy
of such devices requires low defect density templates as described in the previous section and
the ability to control n- and p-doping in AlGaN with high Al-content. 320 nm UV LEDs with
milli-Watt emission power and 298 nm LEDs have been demonstrated. For the fabrication
process the biggest issues are light extraction and heat dissipation. To solve these issues
heterostructure design, simulation and growth as well as chip design and device fabrication
106
interact strongly. The resulting concepts of flip-chip UV-LEDs with interdigitated fingercontacts, micropixel contacts or nanopixel contacts have proven to increase output power in a
broad spectral range from 380 – 320 nm.
(a)
(b)
(a) Photographic image of a 380 nm flip-chip UV-LED with micropixel contacts. (b) Emission spectra of
InGaN RPG disk laser below and above the threshold. The inset shows the far-field intensity distribution.
The beam divergence is approximately 20 mrad.
Surface Science Research
Self-assembled ultra-thin molecular layers on solid substrates have emerged to an important
material system for novel applications like biosensors or lab-on-the-chip concepts. For such
applications a profound understanding of the interfacial structure and formation between the
two material systems is required. We investigate the interface reactions between organic
molecules and semiconductor surfaces including the technologically important III-nitrides. In
particular we aim for an understanding of the general factors that determine the moleculesemiconductor interaction on an atomic scale. In the past two years we were able to
demonstrate that the adsorption of molecules can cause a complex modification of the surface
electronic properties of semiconductor materials, depending on the exact structural aspects of
the respective interface formation. We have developed and established optical techniques for
the non-destructive in-situ monitoring of molecular film growth in a sub-monolayer range.
We could show that molecular orbitals of ordered organic films can be observed as optical
anisotropies with RAS measurements. We have successfully demonstrated that a new UVRAS setup (operating up to 9.5 eV) allows a direct observation of molecular orbitals of small
molecules. By the help of the UV-RAS we could realize the controlled preparation of organic
sub-monolayers on GaAs(001) surfaces. At these ultra-thin layers we could correlate the RAS
signatures with transitions between electronic states of the molecules as determined by single
molecule spectroscopy by STS. Our measurements show that the electronic properties of
adsorbed molecules depend significantly on their respective bonding mechanism
(chemisorption or physisorption). The bonding mechanism on the other hand is determined by
molecular properties (electrophilicity and aromaticity) as well as surface properties (dimer
structure and stoichiometry). Based on these insights into the nature of organic/inorganic
bonding mechanisms we are extending our investigations to the characterization of organic
adsorbate layers on other III-V materials and particularly group-III nitrides (InN, GaN,
InGaN) and 2D nano-materials, e.g. 2D silicon. For this purpose well defined III-nitride
surface structures are needed. We therefore explore the atomic surface structure of these
materials upon subsequent molecule adsorption. On InxGa1-xN (0001) (0≤x≤1) we established
the preparation of clean reconstructed surfaces with (1x1), (1+1/6), (2x2) and (√3x√3)R30°
107
symmetries under ultra-high vacuum conditions. The amount of surface-indium determines
the atomic and electronic structure of these surfaces giving rise to also influence the interface
formation with molecular layers.
Left: UV-RAS spectra of pyrrole adsorbed on GaAs(001)(4x2) (orange line) and the clean GaAs surface (grey
line). Right: Single molecule STS spectrum of adsorbed pyrrole (shown in the inset STM image) indicating
possible UV transitions that could contribute to the UV-RAS anisotropies.
108
9.4.3 Books
Blue and green-emitting laser diodes
Michael Kneissl & Jens Raß
book chapter to be published in Landolt-Börnstein VIII-Vol. B Part III – Laser System
(2010). – IN PRINT.
9.4.4 Publications
1.
Emission characteristics of InGaN multi quantum well light emitting diodes with
differently strained InAlGaN barriers
T. Kolbe, A. Knauer, H. Wenzel, S. Einfeldt, V. Küller, P. Vogt, M. Weyers, M.
Kneissl
phys. stat .sol. (c) 6, No. S2, S889-S892 (2009)
2.
Optimization of InGaN/(In,Al,Ga)N based near UV-LEDs by MQW strain
balancing with in-situ wafer bow sensor
A. Knauer, T. Kolbe, S. Einfeldt, M. Weyers, M. Kneissl, and T. Zettler
phys. stat .sol. (a) 206, 211-214 (2009)
3.
Epitaxial Lateral Overgrowth on (2-1-10) a-Plane GaN with [0-111] Oriented
Stripes
T. Wernicke, U. Zeimer, C. Netzel, F. Brunner, A. Knauer, M. Weyers, M. Kneissl
J. Crystal Growth 311, 2895(2009)
4.
MOVPE growth for UV-LEDs
A. Knauer, F. Brunner, T. Kolbe V. Küller, H. Rodriguez. S. Einfeldt, M. Weyers and
M. Kneissl
Proc. SPIE 7231, 72310G (2009)
5.
Ultraviolet laser diodes on AlN and sapphire substrates
Michael Kneissl, Zhihong Yang, Mark Teepe, Noble M. Johnson
Proc. SPIE 7230, 7230-13 (2009)
6.
Growth mode of InGaN on GaN (0001) in MOVPE
M. Pristovsek, J. Stellmach, M. Leyer, M. Kneissl
phys. stat .sol. (c), 1– 5 (2009) / DOI 10.1002/pssc.200880915
7.
Volmer-Weber growth mode of InN quantum dots on GaN by MOVPE
Christian Meissner, Simon Ploch, Markus Pristovsek, Michael Kneissl
phys. stat .sol. (c), 6, S2, S545 (2009). (DOI 10.1002/pssc.200880872)
8.
Growth Mode and Shape of InN Quantum Dots and Nanostructures grown by
Metal Organic Vapour Phase Epitaxy
S. Ploch, C. Meissner, M. Pristovsek, M. Kneissl
phys. stat .sol. c 6, s574 (2008)./ DOI 10.1002/pssc.200880938
9.
Adsorption geometry of hydrocarbon ring molecules on GaAs(001)c4x4
R. Paßmann, T. Bruhn, T.A. Nilson, B. O. Fimland, M. Kneissl, N. Esser, P.Vogt
Phys. Status Solidi B 246 (Feature Article), 1504-1509 (2009) /DOI
10.1002/pssb.200945178
109
10.
Bonding configuration of cyclopentene on InP(001)(2x4) surface
Regina Passmann, Priscila Favero, Wolf Gero Schmidt, Ronei Miotto, Walter Braun,
Wolfgang Richter, Michael Kneissl, Norbert Esser and Patrick Vogt
Phys. Rev. B 80, 125303 (2009)
11.
Polarization of eigenmodes in laser diode waveguides on semipolar and nonpolar
GaN
Jens Raß Tim Wernicke, Wolfgang G. Scheibenzuber, Ulrich T. Schwarz, Jan Kupec,
Bernd Witzigmann, Patrick Vogt, Sven Einfeldt, Markus Weyers, Michael Kneissl
phys. stat. sol. (RRL) 4, 1-3 (2010). (DOI 10.1002/pssr.200903325)
12.
Adsorption of cyclopentene on GaAs(001) and InP(001), a comparative study by
synchrotron-based core level spectroscopy
R. Paßmann, T. Bruhn, B. O. Fimland, W. Richter, M. Kneissl, N. Esser, P. Vogt
World Scientific WSPC - Proceedings of the workshop on synchrotron radiation and
nano-structures 1, (2009), ISBN-13: 978-981-4280-83-9
13.
Structure investigations of nonpolar GaN layers
W. Neumann, A. Mogilatenko, T. Wernicke, E. Richter, M. Weyers, M. Kneissl
J. Microsc. 237, 308 (2009)
14.
Deep UV nitride-based light emitting diodes – applications and challenges
M. Kneissl, T. Kolbe, N. Lobo, J. Stellmach, A. Knauer, V. Küller, H. Rodriguez, S.
Einfeldt, M. Weyers
Proceedings of the 6th China International Forum on Solid State Lighting (2009)
15.
Laser Scribing for Facet Fabrication of InGaN MQW Diode Lasers on
Sapphire Substrates
J. R. van Look, S. Einfeldt, V. Hoffmann, A. Knauer, M. Weyers, P. Vogt and M.
Kneissl
IEEE Photonics Technology Letters 22 (6), 416 (2010)
16.
Adsorbate-induced modification of the surface electric field at GaAs(001)-c(4x4)
measured via the linear electro-optic effect
T. Bruhn, R. Paßmann, B. O. Fimland, M. Kneissl, N. Esser, P. Vogt
phys. stat. sol. (b) 247 (8), 1941 (2010).
17.
Internal efficiency of InGaN light-emitting diodes: Beyond a quasi-equilibrium
model
W. W. Chow, M. H. Crawford and J. Y. Tsao, M. Kneissl
Appl. Phys. Lett. 97, 121105 (2010).
18.
InGaN/GaN Disk Laser for Blue-Violet Emission Wavelengths
R. Debusmann, N. Dhidah, V. Hoffmann, L. Weixelbaum, U. Brauch, T. Graf, M.
Weyers, M. Kneissl
IEEE Photonics Technology Letters 22 (9), 652 (2010).
19.
Growth of semipolar (10-1-3) InN on m-plane sapphire using MOVPE
Duc Dinh, M. Pristovsek, R. Kremzow, M. Kneissl
phys. stat. sol. (RRL) 4, No. 5–6, 127 (2010).
20.
Well width study of InGaN multiple quantum well structures for blue-green
emitters
V. Hoffmann, C. Netzel, U. Zeimer, A. Knauer, S. Einfeldt, F. Bertram, M. Weyers, G.
Tränkle, M. Kneissl
J. of Crystal Growth (2010), doi:10.1016/j.jcrysgro.2010.09.013
110
21.
Uniformity of the wafer surface temperature during MOVPE growth of GaNbased laser diode structures on GaN and sapphire substrate
V. Hoffmann, A. Knauer, C. Brunner, S. Einfeldt, M. Weyers, G.Tränkle, K. Haberland,
J.-T. Zettler, M. Kneissl
J. of Crystal Growth (2010), doi:10.1016/j.jcrysgro.2010.09.048
22.
Advances in InAlGaN-based deep UV light emitting diode technologies
M. Kneissl, T. Kolbe, N. Lobo, J. Stellmach, A. Knauer, V. Kueller, H. Rodriguez, S.
Einfeldt, M. Weyers
Proceedings of the 12th International Symposium on the Science and Technology of
Light Sources and the 3rd International Conference on White LEDs and Solid State
Lighting, LS-WLED 2010, 265-268 (2010).
23.
(In)AlGaN deep ultraviolet light emitting diodes with optimized quantum well
width
T. Kolbe, T. Sembdner, A. Knauer, V. Küller, H. Rodriguez S. Einfeldt, P. Vogt, M.
Weyers and M. Kneissl
phys. stat. sol. (a) 207, 2198-2200 (2010).
24.
Optical polarization characteristics of ultraviolet (In)(Al)GaN multiple quantum
well light emitting diodes
T. Kolbe, A. Knauer, C. Chua, Z. Yang, H. Rodrigues, S. Einfeldt, P. Vogt, N.M.
Johnson, M. Weyers and M. Kneissl
Appl. Phys. Lett. 97, 171105 (2010).
25.
Carrier injection in InAlGaN single and multi-quantum-well ultraviolet
light emitting diodes
T. Kolbe, T. Sembdner, A. Knauer, V. Küller, H. Rodriguez S. Einfeldt, P. Vogt, M.
Weyers and M. Kneissl
phys. stat. sol. (c) 7, 2196-2198 (2010).
26.
Metalorganic Vapor Phase Epitaxy of InN on GaN using tertiary-butylhydrazine
as Nitrogen Source
R. Kremzow, M. Pristovsek, J. Stellmach, Ö. Savaş, M. Kneissl
Journal of Crystal Growth (2010), DIO:10.1016/j.jcrysgro.2010.03.019
27.
Growth of AlGaN and AlN on Patterned AlN/Sapphire Templates
V. Küller, A. Knauer, F. Brunner, U. Zeimer, H. Rodriguez, M. Weyers, and M. Kneissl
Journal of Crystal Growth (2010), doi:10.1016/j.jcrysgro.2010.06.040
28.
Enhancement of light extraction in UV LEDs using nanopixel contact design with
Al reflector
N. Lobo, H. Rodriguez, A. Knauer, M. Hoppe, S. Einfeldt, P. Vogt , M. Weyers and M.
Kneissl
Appl. Phys. Lett. 96, 081109 (2010).
29.
Effects of low charge carrier wave function overlap on internal quantum efficiency
in GaInN quantum wells
Carsten Netzel, Veit Hoffmann, Tim Wernicke, Arne Knauer, Markus Weyers, Hans
Wenzel, and Michael Kneissl
phys. stat. sol. (c) 7, 1872 (2010).
111
30.
Influence of the wave function overlap in GaInN quantum wells on the
temperature and excitation power dependent photoluminescence intensity
C. Netzel, V. Hoffmann, T. Wernicke, A. Knauer, M. Weyers, M. Kneissl, and N.
Szabo
Journal of Applied Physics 107, 033510 (2010).
31.
Orientation control of GaN {11-22} and {10-13} grown on (10-10) sapphire by
metal-organic vapor phase epitaxy
S. Ploch, M. Frentrup, T. Wernicke, M. Pristovsek, M. Weyers, M. Kneissl
J Cryst. Growth, 312, 2171 (2010).
32.
Determination of the complex linear electro-optic coefficient of GaAs and InP
M. Pristovsek
physica status solidi (b) 247 (2010) 1974-1978 DOI:10.1002/pssb.200983950
33.
Facet formation for laser diodes on nonpolar and semipolar GaN
Jens Raß, Tim Wernicke, Raimund Kremzow, Wilfred John, Sven Einfeldt, Patrick
Vogt, Markus Weyers, Michael Kneissl
phys. stat. sol. (a) 207, 1361–1364 (2010) / DOI 10.1002/pssa.200983425
34.
GaN-based Ultraviolet Light-Emitting Diodes with Multifinger Contacts
H. Rodriguez, N. Lobo, S. Einfeldt, A. Knauer, M. Weyers and M. Kneissl
phys. stat. sol. (a), (2010), DOI: 10.1002/pssa.201026193
35.
Application of GaN-based deep ultraviolet light emitting diodes – UV-LEDs –
for Water disinfection
M.A. Würtele, T. Kolbe, A. Külberg, M. Lipsz, M. Weyers, M. Kneissl, M. Jekel
Water Research 45, 1481 (2011).
36.
Optical and structural properties of InGaN/(AlIn)GaN multiple quantum wells
grown at different temperatures and In supply
U. Zeimer, U. Jahn, V. Hoffmann, M. Weyers, M. Kneissl
Journal of Electronic Materials, Vol. 39, 677 (2010),
37.
High aluminium content and high growth rates of AlGaN in a close-coupled
showerhead MOVPE reactor
J. Stellmach, M. Pristovsek, Ö. Savas, J. Schlegel, E. V. Yakovlev, M. Kneissl
Journal of Crystal Growth 315, 229 (2011).
38.
MOCVD growth of InGaN/GaN QDs for green emitters
A. Kadir, Ch. Meissner T. Schwaner, M. Pristovsek, M. Kneissl
Proc. of the Photonics 2010. New Delhi: Viva Books Private Ltd, 2010, S. 231-231
39.
Surface morphology of homoepitaxial GaN grown on non and semipolar GaN
substrates
Tim Wernicke, Simon Ploch, Veit Hoffmann, Arne Knauer, Markus Weyers, and
Michael Kneissl
phys. stat. sol. (b) 248, No. 3, 574 (2011).
40.
Crystall orientation of GaN layers on (10-10) Sapphire
M. Frentrup, S. Ploch, M. Pristovsek, M. Kneissl
phys. stat. sol. (b) 248, No.3, 583 (2011)
41.
Application of GaN-based deep ultraviolet light emitting diodes – UV-LEDs – for
Water disinfection
M.A. Würtele, T. Kolbe, A. Külberg, M. Lipsz, M. Weyers, M. Kneissl, M. Jekel
Water Research 45, 1481 (2011).
112
42.
Advances in group III-nitride based deep UV light emitting diode technology
M. Kneissl, T. Kolbe, C. Chua, V. Kueller, N. Lobo, J. Stellmach, A. Knauer, H.
Rodriguez, S. Einfeldt, Z. Yang, N. M. Johnson, M. Weyers
Semicond. Sci. Technol. 26, 014036 (2011).
43.
Adsorbate-induced modification of the surface band bending at GaAs(001)
surfaces
T. Bruhn, B. O. Fimland, M. Kneissl, N. Esser, P. Vogt
Phys. Rev. B 83, 045307 (2011)
44.
High aluminium content and high growth rates of AlGaN in a close-coupled
showerhead MOVPE reactor
J. Stellmach M. Pristovsek, Ö. Savas, J. Schlegel, E. V. Yakovlev, M. Kneissl
Journal of Crystal Growth 315, 229 (2011).
45.
Polarization dependent photoluminescence studies of semipolar and nonpolar
InGaN quantum wells
L. Schade, U.T. Schwarz, T. Wernicke, M. Weyers, M. Kneissl
phys. stat. sol. (b) 248, No.3, 638 (2011).
46.
Growth Mechanism of Embedded Self-Organized InN Quantum Dots on GaN
(0001)
in MOVPE
F. Ivaldi, J. Domagala, S. Kret, Ch. Meissner, M. Pristovsek, M. Högele, and M.
Kneissl
Jpn. J. of Appl. Phys. 50, No. 3, 031004 (2011).
47.
Optical polarization of UV-A and UV-B (In)(Al)GaN multiple quantum well
light emitting diodes
T. Kolbe, A. Knauer, J. Stellmach, C. Chua, Z. Yang, H. Rodrigues, S. Einfeldt, P.
Vogt, N.M. Johnson, M. Weyers and M. Kneissl
Proc. SPIE 7939, 79391G (2011).
48.
AlGaN-based Ultraviolet Lasers - Applications and Materials Challenges
Michael Kneissl, Tim Kolbe, Jessica Schlegel, Joachim Stellmach, Chris Chua, Zhihong
Yang, Arne Knauer, Markus Weyers, Noble M. Johnson
Technical Digest, CLEO: 2011 (Optical Society of America, Washington, DC, 2011),
JTuB1 (2011).
49.
In-situ optical spectroscopy and electronic properties of pyrrole sub-monolayers
on Ga-rich GaAs(001)
T. Bruhn, B. O. Fimland, M. Kneissl, N. Esser, P. Vogt
J. Nanoparticle Research (2011) , DOI: 10.1007/s11051-011-0340-0
50.
Direct observation of dimer flipping at H-terminated InP and GaP (001) surfaces
P. Kleinschmidt, H. Döscher, P. Vogt, T. Hannappel
Phys. Rev. B 83, 155316 (2011)
113
9.4.5 Invited Talks
Prof. Dr. Michael Kneissl
Ultraviolet Laser Diodes on AlN and Saphire Substrats
SPIE Photonics West 2009, San Jose, Germany, January 2009
Semiconductor Nanophotonics Research at TU Berlin
Seminar at Middle East Technical University (METU), Ankara,
Turkey, April 2009
Deep UV nitride-based light emitting diodes Applications
and Challenges
China Solid State Lighting Conference 2009, Shenzen, China,
October 2009
Ultraviolet LEDs and Lasers - Applications and Challenges
iNOW 2009, Stockholm, Sweden, August 2009
From UV LEDs to green lasers – Challenges and progress in
the development of GaN based light emitters
Seminar at Varian Semiconductor Equipment Associates,
Gloucester, MA, USA, November 2009
MOVPE of (In)AlGaN materials for UV light emitters
Aixtron Workshop 2009, Shenzen, China, October 2009
Advances in InAlGaN-based deep UV light emitting diode
technologies
3rd International Conference on White LEDs and Solid State
Lighting LS12-WhiteLED3, Eindhoven, Netherlands, July 2010
Advances and applications of GaN-based UV light emitting
diode technologies
International Nano-Optoelectronics Workshop (iNOW 2010),
Beijing, China, August 2010
Group III-nitride based UV light emitters – applications and
materials challenges
Seminar at the Paul Drude Institut für Festkörperelektronik,
Berlin, Germany, March 2010
InAlGaN-based UV LEDs - Applications and Challenges
Physikalisches Kolloquium, Otto-von-Guericke University,
Magdeburg, Germany, May 2010
Fortschritte bei der Entwicklung von LEDs im ultravioletten
Spektralbereich
VDI Fachtagung LED, Düsseldorf, Germany, November 2010
114
LEDs im fernen UV - Stand und mögliche Anwendungen
FutureLED Workshop, Berlin, Germany, May 2010
Dr. Abdul Kadir
Growth mechanism of InGaN quantum dots by
metalorganic vapour phase epitaxy
Alexander von Humboldt Network Meeting, Duisburg,
April 2010
Advanced In-situ Monitoring of Metal Organic Vapour
Phase Epitaxy
SemicoNano, Tokushima, Japan, August 2009
Metal-Organic Vapour Phase Epitaxy of Indium Nitride
Universidad Politécnica de Madrid (ETSIT-UPM), Madrid,
Spain, August 2010
In-situ Monitoring of Doping with Reflectance Anisotropy
Spectrocopy
3rd NanoCharm Workshop on Non-Destructive Real Time
Process Control, Berlin, Germany, October 2010
Dr. Patrick Vogt
Adsorption of small organic ring molecules on III-V(001)
surfaces
Epioptics-11, Erice, Italy, July 2010
Dr. Patrick Vogt
Organic/inorganic interfaces: basic concepts
Epioptics-11, Erice, Italy, July.2010
Dr. Patrick Vogt
Devices based on InGaAs Quantum Dots
PV-Technology Development & Market-Trends,
National Technical University of Athens (Ethniko Metsovio
Polytechnio), Athinai (Athen), Greece, October 2010
Dr. Patrick Vogt
Growth and Characterization of In(Ga)N Compounds for
Device Applications
PV-Technology Development & Market-Trends,
National Technical University of Athens (Ethniko Metsovio
Polytechnio), Athinai (Athen), Greece, October 2010
Dr. Tim Wernicke
Growth of nonpolar nitrides: the substrate dilemma
DPG Frühjahrstagung 2009, Dresden, Deutschland, March 2009
Dr. Tim Wernicke
Growth of nonpolar nitrides: the substrate dilemma
Seminar at the University of Cambridge, UK, July 2009
Dr. Tim Wernicke
In-incorporation on semipolar surfaces for blue-green lasers
Seminar at the IAF, Freiburg, July 2010
Dr. Tim Wernicke
In-incorporation on semipolar surfaces for blue-green lasers
E-MRS Fall meeting, Warschau, Poland, September 2010
115
Dr. Tim Wernicke
Semipolar quantum wells for lasers
PolarCoN Summerschool, Ulm, Germany, October 2010
Dipl.-Phys. Tim Kolbe
Water disinfection with GaN-based deep ultraviolet light
emitting diodes
nANO meets water II, Oberhausen, Germany, Fraunhofer
UMSICHT, November 2010
Dipl.-Phys. Simon Ploch
Growth of semipolar InN, GaN and AlN on m-plane
sapphire
PolarCoN Summerschool, Günzburg, Germany, October 2010
116
9.4.6 Diploma, Master-, and Bachelor Theses
Eric Bauch
Nitrogen-Vacancy defects in diamond for sub-millimeter
magnetometry
28.07.2010
Amelie Biermann
Morphologie und atomare Struktur von In(Ga)N Oberflächen
12.10.2010
Martin Frentrup
Epitaxie und Charakterisierung von nicht- und semipolaren
Galliumnitrid-Heterostrukturen
17.03.2010
Marc Hoffmann
GaAs-basierte Tunneldioden
18.07.2009
Michael Högele
Epitaxie und Charakterisierung von InGaN
Quantenpunktstrukturen
30.10.2009
Michael Hoppe
Elektrooptische und elektrothermische Untersuchungen an
Leuchtdioden im ultravioletten Spektralbereich
03.09.2010
André Kruse
Wachstumsmodi von InGaN Schichten in der Metallorganischen
Gasphasenepitaxie
28.07.2010
Igor Kuznecov
Metallorganische Gasphasenepitaxie von AlGaN-Schichten mit
hohem Aluminiumgehalt
12.11.2010
Martin Martens
Optoelektronische Eigenschaften und spektrale Empfindlichkeit
von AlGaN-basierten Photodetektoren
03.09.2010
Linda Riele
Bindungsstruktur und Selbstorganisation von MetallPhtalocyaninen auf GaAs(001)-Oberflächen
10.10.2009
Özgür Savas
Dotierung und Charakterisierung von (Al)GaN Schichten
hergestellt mittels Metallorganischer Gasphasenepitaxie
06.05.2009
Matthias Schmies
In-Situ Rastertunnelmikroskopie an Nanostrukturen in der
Metallorganischen Gasphasenexpitaxie
02.03.2010
Katrin Sedlmeier
CuInxGa(1-x) Se2 Nanokristalle: Wachstum mittels chemischer
Gasphasenabscheidung und Charakterisierung
11.08.2010
Toni Sembdner
Analyse der Lumineszens- und Strom-Spannungs-Charakteristik
von Lichtemittern im UV Spektralbereich
17.03.2010
Alexander Wolf, B.Sc. Charakterisierung von AlGaN-basierten MSM Photodetektoren
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21.12.2010

Institute of Solid State Physics Institut für Festkörperphysik 2009

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