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Regional-Use EELS Chemical Imaging System William Rankin NanoUtah15 October 13, 2015
Regional-Use EELS Chemical Imaging System
William RankinNanoUtah15
October 13, 2015
What is EELS?• Analysis of the energy distribution of
electrons that have come through a sample
• Energy resolution < 1eV– Can distinguish between chemical states
• Sub-nanometer spatial resolution• Can quantify light and heavy
elements• High analytical sensitivity• Reveals information about:
– Bonding/valence state– Nearest-neighbor atomic
structure– Dielectric response– Free electron density– Band gap– Specimen thickness
Williams, D., & Carter, C. (2009) Transmission electron microscopy: A textbook for materials science. (2nd ed.)
Energy-loss (eV) →
v
280 290 300 310 320
Graphite
Diamond
Differences between C edge between graphite and diamond
Change in Cu L edge as Cu metal is oxidized
Energy-loss (eV) →
v
920 940 960 980
CuO
Cu
L3
L2
[1] [1]
[1] Chapter 40 in Transmission Electron Microscopy by David B. Williams and C. Barry Carter, Plenum Press, New York, 1996.
Electron Loss Near Edge Spectroscopy
Chapter 40 in Transmission Electron Microscopy by David B. Williams and C. Barry Carter, Plenum Press, New York, 1996.
Data and images courtesy of Gatan
Data and images courtesy of Gatan
Energy Filtering
Imaging
Diffraction
Filter out the inelastically scattered electrons
http://eels.kuicr.kyoto-u.ac.jp/eels.en.html
In Conclusion
• EELS is a powerful technique that can quantify and characterize the entire periodic table, including light elements.
• EELS has a combination of analytical and spatial resolution that is unmatched by other techniques.
• We are currently working on an MRI proposal to bring EELS to the University of Utah.– Contact Dr. Brain van Devener if you are interested in
supporting this proposal– [email protected]
Overview of electron energy loss spectroscopy (EELS) and energy filtered TEM imaging
Dr. Paolo Longo
Wednesday, October 21st at 2:15 pmRoom 2650 Sorenson Molecular Biotechnology
Building (SMBB)
No visible Grain Boundary
2.761 Å
Fourier filtered image
Dislocation structures at the Grain boundary
coun
ts
eV
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coun
ts
1850 1900 1950 2000 2050 2100 2150 2200 2250eV
coun
ts
eV
11000
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coun
ts
1850 1900 1950 2000 2050 2100 2150 2200 2250eV
Si peak at 1839 eV Sr L2,3 peaks
Grain Boundary
Grain
eV1900 2000
EELS
2100 2200
~8º TILT BOUNDARY IN THE SrTiO3 POLYCRYSTAL
GB23x4
MX23x4
Dist 5 nm
VG microscope
