ELECTRON ENERGY LOSS SPECTROSCOPY

GÖZDE ARIBAL
20823751
AYKUT BİLİR
20823842
BORGA DERBENT
20823966
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What is the EELS ?
The process of historical development
How does it work ?
Components and properties
Why is it used ?
Advantages and Disadvantages
Compare with EDX
Applications
Summary
References
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Analytical technique
Quantitative analysis
Analysis of the inelastic scattering suffered by the
transmitted electron beam with measurement of
the electron energy distribution
Capable of giving structural and chemical
information
Electron spectrometer
Figure 1
High-resolution electron energy loss spectroscopy (EELS) is a highsensitivity, non-destructive technique for the study of surface and
adsorbate vibrations and low-energy electronic excitations.
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James Hillier
• RF Baker in the mid 1940s
• Research 1990s due to
advance in microscope
instrumentations and
vacuum technology
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Can be obtained experimentally
In elastic scattering of X-ray photons or
optical measurements
Change in momentum and direction of
propaganation
Change in internal degrees of freedom
Figure 2
A typical EELS spectrum from an thin film
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Magnetic field is between two parallel
plates.
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Objective aperture
Specimen
Lens
Collector aperture
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Figure 3
Photograph of the first electron microanalyzer (Hiller and Baker 1944)
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The measurements of
Local properties
Including specimen thickness
Mechanical and electronical
Chemical composition
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Higher core-loss signal
• Higher ultimate spatial resolution
• Absolute, standardless quantification
• Structural information available
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Higher spectral background
Very thin specimen needed
Possible inaccuracy in crystals
More operator intensive
Table 1.Comprasion between EELS and EDX.
Table 2. X-ray fluorescence yield for K-,L- and Mshells as a function of atomic number, from Krause (1979)
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Thickness measurements
Pressure measurements
Analytical electron microscopy (AEM)
Electron energy-loss spectroscopy (EELS) is
an analytical technique that measures the
change in kinetic energy of electrons after they
have interacted with a specimen.
1) Journal de Physique IV , Colloque C7 ,
supplément au journal de physique III ,Volume
3
2) R.F. EGERTON Electron Energy Loss
Spectroscopy in The Electron Microscope 3.
Edition
3) Yüksek Lisans Tezi NANO ÖLÇEKLİ VANANYUM
OKSİT İNCE FİLMLERİN YAPISAL VE
ELEKTRİKSEL KARAKTERİZASYONU Ogeday
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