An Introduction to Auger Electron Spectroscopy
Ha Nguyen
CHM 1046H
Application
* Auger Depth Profiling=>depth below the surface.
* Identification of Microscopic.
* Scanning Auger Microscopy.
* Corrosion and oxidation.
*Quantitation of light element surface film.
* Determine sex and age based on the ratio of Ca/P of different bone sites.
The Auger process
The electron detector
The schematic of an arrangement
The electron energy analyzer
Detector communicates with energy respect to time data.
- The primary electron from electron gun collides with 1s-shell electron .
- The secondary e- gets excited and dispersed.
- Electron from 2s-shell fills the vacancy and emits Auger electron.
Its function is to disperse the secondary electron and transfer it to electron detector.
- UHV environment - Electron gun
- Electron analysis - Electron detector
- Data acquisition
The data is analyzed to find out the data peak
The de-excitation of electron
- If the source atom has been closer to the surface, then a greater fraction of the emitted electrons would have been detected.
* Peaks in the spectrum identify the elemental composition of the sample surface.
Conclusion
Auger Electron Spectroscopy is the best instrument to study spatial resolution, light element, and surface depth by determining the identification physical and chemical characteristics of the surface sample.
The energy detected by an expression
References:
Eke: the kinetic energy
EK: kinetic energy of electron in the K shell
EL: kinetic energy of electron in the L shell
ϕ: work function of the detector
Introduction
- Gaurv, Nair. Mithun, P. Naveen, S. Nipin, L. “Auger Electron Spectroscopy”. Web. March 22, 2016.
http://www.mecheng.iisc.ernet.in/~bobji/mspc/assign/AES.htm
- University At Albany. “Auger Electron Spectroscopy (AES). Elementals and Appilcation”. Web. March 26th, 2016.
http://chemistry.st-and.ac.uk/staff/gh/teaching/CH5711/Further%20reading/auger.pdf
- Determining and analyzing the outermost chemical surface composition.
- By determining kinetic energy of Auger electron => atom is defined.
* Plot of spectrum is the back scattered electrons versus kinetic energy per unit energy interval .
History
Auger Electron Spectroscopy
Lise Meitner
- An Austrian physics (1878-1968).
- Discover this effect independently in 1923.
- Her contribution was reported in the journal Zeitschrift für Physik.
Pierre Auger
- A French physics (1899-1993), was credited in the most scientific community in 1925.