Nanotechnology

Nanotechnology
Eleanor Campbell
Dept. of Physics, Göteborg University
What is Nanotechnology ?
Nano: 10-9; ”Dwarf”
Length Scales in Physics
• 0,000 000 000 000 000 000 000 000 000 000 000 01 meter
Plancklängden, strängteori
• 0,000 000 000 000 000 001 meter
Elementarpartikelfysik; elektroner, protoner, ...
• 0,000 000 000 000 01 meter
Kärnfysik
• 0,000 000 000 1 meter
Atomfysik
Nanofysik, kemisk fysik..
0,000 000 001 meter
•1 meter
Kondenserad materias fysik, biofysik, geofysik...
•100 000 000 000 000 000 000 000 000 meter
Astrofysik, kosmologi
Size Comparison
Earth 10 7 m
-8
10
Football 0.1 m
Fullerene
-9
10 m
-8
10
100 000 nm
1 nm
Nanotechnology:
Nanostructures are at the confluence of the smallest
human-made devices and the largest molecules of living
things. Nanoscale science and engineering refer to the
fundamental understanding and resulting technological
advances arising from the exploitation of new physical,
chemical and biological properties of systems that are
intermediate in size between isolated atoms and
molecules and bulk materials, where the transitional
properties between the two limits can be controlled
M. Roco, NSF (2001)
e
+
Ze
e
Atom
e
Bulk
Multidisciplinary Research & Engineering
Physics - Chemistry - Biology – Medicine –
Computer Science - Materials Science - Engineering
Material on the nanoscale is not just smaller it is also
fundamentally different (”a special kind of small”):
Properties can be very dependent on the number of atoms
Quantum effects can become important
The Beginnings of Modern Nanotechnology
1959 ”There is Plenty of Room at the Bottom”
”What would the properties of materials
be if we could really arrange the atoms
the way we want them? They would be
very interesting to investigate
theoretically. I can't see exactly what
would happen, but I can hardly doubt
that when we have some control of the
arrangement of things on a small scale
Richard Feynman we will get an enormously greater range
Theoretical Physicist of possible properties that substances
NP 1965 for QED
can have, and of different things that we
can do. ”
Modern Nanotechnology Laboratory
Early Nanotechnologists
Egyptian Pottery Makers
Egyptian Gold Workers
Medieval Stained Glass Windows also make use of
Metallic Nanoparticles to Produce the Strong Colours
The properties of
metallic nanoparticles
are very dependent on
size.
The difference today is that we
understand the physics behind
the phenomenon and can
control the size, shape and
behaviour of the particles to a
much greater extent
Surface Plasmon in a
Metallic Nanoparticle
Gold and Silver nanoparticles
have plasmon resonances in
the visible range. The resonant
frequency depends on the size
of the particles (also on shape
and surrounding material)
Dark Field Image of Ag Nanoparticles in Optical Tweezer Setup
M. Käll
D. Hanstorp
Chalmers/GU
Particle A is trapped and moved by a laser beam
The colour changes when the 2 particles come close
Qdot: using functionalised CdSe
clusters for labelling biological
materials.
Double-labeling of mitochondria and
microtubules in NIH 3T3 cells
The colours of the particles depend on their size used instead of dye molecules
Two Approaches:
Top Down
and
Bottom Up
The meeting of these 2 approaches is opening up many exciting
opportunities
Two Approaches to Nanotechnology
Top Down
lithography
Bottom Up
Self-assembly
If we have been making use of
”nanotechnology” for thousands of years
why is it such a hot topic now???
It is only very recently that we have been
able to see and manipulate individual
atoms
This is extremely important to understand
how the manipulation of material on the
atomic/nanometer level can lead to new
properties
To manipulate material on the atomic
level it helps to ”see” the atoms
High resolution electron microscopy has made great
advances and it is now possible to see individual atoms,
even as smal as Li (1Å resolution).
Scanning Tunnel Microscope
Binnig and Röhrer, NP 1986
Possible to ”see” and
MANIPULATE individual
atoms
”atom”
Iron atoms on Copper
Don Eigler (IBM)
Catalytic behaviour of Palladium Clusters
U. Heiz, Ulm
C2H2 -> C4H6, C4H8 or C6H6
Catalytic Converters:
Clusters of platinum, rhodium and palladium atoms break
down unwanted exhaust products, CO, hydrocarbons and NOx
Other Catalytic Applications:
Gold clusters have been
used in Japanese hi-tech
toilets since 1992 as ”odour
neutralisers”
”Open Sesame: The Neorest's lid
automatically rises when one approaches
it. Ladies need not worry, as the
automated seat then waits to see if one
needs to sit or stand.”
graphite
sp2 hybridised
diamond
sp3 hybridised
Carbon Clusters: Fullerenes
Nobel Prize in Chemistry, 1996
”Buckminsterfullerene”
discovered in 1985
Produced as purified material
in 1990
The extreme flexibility of the carbon atom lies behind all of
organic and bio-chemistry. It is also responsible for the
wide range of nano-carbon materials that are studied
today.
Where it started. Astrophysics/chemistry
Gas Clouds in Space:
What molecules are present?
Kroto: µ-wave spectroscopy of
cyanopolyynes.
These long chain molecules
(consisting of C, H and N) are
found in interstellar gas clouds.
Kroto saw signatures in µwave
spectra from carbon-rich stars
that indicated they could also be
present there, and were probably
formed, in these environments.
He wanted a way to test the
formation of these molecules
under conditions that would be
close to the interior of red giant
stars.
Smalley: well-known chemical physicist who had made pioneering
studies in molecular laser spectroscopy. He was an excellent ”machine
builder”
Smalley had developed a method for making clusters of atoms from
materials that were difficult to vaporise: Smalley source
Could this apparatus mimic the
conditions in carbon-rich stars?
Curl, Kroto and Smalleys discovery, 1985
Suggestion that hollow, cage-like
structures could explain the ”magic
numbers” in the mas spectrum
Isaac Asimov: ”The most exciting phrase to hear in science, the one
that heralds the most discoveries, is not 'Eureka!' but 'That's funny...' ”
A new form of pure carbon
Kroto named the new
molecule”Buckminsterfullerene”
Geodesic Dome
designed by
R. Buckminster Fuller
Krätschmer and Huffmans breakthrough
1990
Macroscopic production
of fullerene-containing
soot using electric arc
discharge
C60 and C70 are soluble in
benzene
Fullerene crystals
NMR (13C)
C60
C70
Medical Applications of Fullerenes
(C-sixty)
Fullerene-based protease
inhibitor (HIV)
Water soluble contrast agent for
magnetic resonance imaging
Yonex Badminton Rackets
Nanospeed Badminton Rackets: Nano-Powered by
Fullerene for more repulsion and speed from a compact
swing. The Yonex nano – structure uses nano – sized
particles of fullerene and carbon. The result is a very fast
head speed creating maximum power.
Actually, the fullerenes don’t
survive – they are simply
being used as a convenient
form of pure carbon!
"Helical microtubules of graphitic carbon", S. Iijima, Nature 354, 56 (1991)
MWNT discovered in 1991 by
Sumio Iijima
– Diameter of ~5-10 nm
– Concentric cylinders of
carbon with a length of
several mm
SWNT in 1993
Why nanotubes?
New ”nanomaterial” with a wide range of interesting
properties
• light weight and record-high elastic modulus
•strongest fibres that can be made
•high thermal conductivity (as good as diamond)
•metallic or semi-conducting (depending on
geometry)
Bulk material is interesting for composite materials e.g.
smart clothing, conducting paper, modifying polymer
properties......
Quasi-one dimensional structures - Theoreticians love them!
Nanotube Dimensions
Scaled to 10 cm
diameter a
typical nanotube
would reach
from Göteborg
to Uddevalla
Västra
Götaland
Wrapping (10,10) SWNT
(armchair)
(0,0)
a1
a2
y
x
Animation: Shigeo Maruyama, Tokyo University
Ch = (10,10)
Wrapping (10,5) SWNT (chiral)
(0,0)
Ch = (10,5)
a1
a2
y
x
Wrapping (10,5) SWNT (chiral)
(0,0)
Ch = (10,5)
a1
a2
y
x
Animation: Shigeo Maruyama, Tokyo University
Zigzag-tube
Chiral-tube
Armchair-tube
All Armchair (n,n) tubes are metallic
Zigzag tubes (n,0) are metallic if n is a multiple of 3
Chiral tubes are semiconducting, bandgap scales with 1/d
or metallic if n-m = 3q
2/3 semiconducting
1/3 metallic
Possibility for carbon-based nanoelectronics
C. Dekker
metal-semiconductor junction
Computing power doubles every 18 months
2nd Law: The cost of a manufacturing plant doubles with every new generation
Future Electronic Applications
Kevin Teixeira, Intel:
”We often get asked,´What comes after silicon?´
But the more interesting question is,´What do you add
to silicon to do something new?´
Carbon nanostructures are one of the most promising future
possibilities to combine with and expand CMOS capabilities
•dimensions (nm)
•electronic properties
•mechanical properties
•thermal conductivity
•ease of production
Field Effect Transistorer
Avouris, IBM
One major aim is to find ways to make new
nanomaterials ”self-assemble” to produce materials
with novel properties
Carbon nanotubes
Semiconductor nanowires, Lund
e.g. Learn how to grow nanodevices
on Si chips
Another aim is to incorporate nanostructures into or onto
normal ”bulk” material to change the properties
Butyl nanoparticles are inserted into clay to
keep the layers apart
Babolat VS NCT
Control
Racquets
Nano-tex
Selfcleaning
lotus leaf
Billions of tiny whiskers
create a thin cushion of air
above the cotton fabric,
smoothing out wrinkles and
allowing liquids to bead up
and roll off without a trace.
Nanostructures surface reduces
contact area and makes super
hydrophobic material
Nanotechnology
Is not just about making small things
Understanding, control and exploitation of
the chemical, physical and biological
properties of matter in the transition region
between atom/molecules and bulk
The tools of Nanotechnology
New Materials and New Applications
Nanotechnology and the environment (including
health issues) followed by lab visit (Chalmers/GU)