Auger Electron Spectroscopy

1. AUGER ELECTRON
SPECTRSCOPY
By-
Manish Sahu
M.Sc. Chemistry (Final)
Sp.- Physical Chemistry

2. Synopsis:-
 Introduction
 History
 Principle of AES
 Steps
 Instrumentation
 Graphical representation
 Advantages
 Disadvantages/Limitation
 Application of AES
 References

3. Introduction:-
 Auger electron spectroscopy (AES), is a widely used
technique to investigate the composition of surfaces of
solids.
 It can also be used for the study of surfaces ,oxidation
catalysis , chemistry of fractured interfaces and more
generally in the area of material science .

4. History:-
 The phenomenon of Auger electron spectroscopy was
first discovered in 1923 by “ Lise Meitner” and later
independently discovered once again in 1925 by “Pierre
Auger”.

5. •Principle of Auger electron spectroscopy
 A fine focused electron beam bombards the sample and
ejects an electron of the inner shell of the atoms.
 The vacancy must be refilled by an electron from a higher
energy level.
 When the higher energy electron fills the hole, the release
of energy is transferred to an electron in an outer orbit
electron.
 The electron has sufficient energy to overcome the binding
energy and the work function to be ejected with a
characteristic kinetic energy.

6.  The ejected electron is referred to as an Auger electron
after Pierre Auger.

7. Principle continue............

8.  Auger electron spectroscopy is a two step phenomenon:-
 Step 1:- Involve the formation of electronically excited ion.
 With x-ray :-
 With electron beam:
 :- Incident electron from the source.
 :- Shows the same electron after it has interacted with“A”
and has lost some of its energy .
 :- Indicates the ejected electron from one of the inner
orbital of “A” .
Steps of Auger process
i iA
i
i

9. •Step2:- Relaxation process
The relaxation of the excited ion can occur in two way:-
A
f
(Auger electron)
(x-ray fluorescence)

10. Instrumentation:-
Fig.- Instrumentation of auger electron spectroscopy

11.  The essential components of an AES
are:-
 UHV Environment.
 Electron gun.
 Electron energy analyzer.
 Electron detector.
 Data recording, processing and out put system.

12. Graphical representation
Fig: - Graph between atomic number and yield per shell vacancy.

13. Advantages :-
 Surface sensitive.
 Elemental and chemical composition analysis by
comparison with standard sample of known
composition.
 Detection of elements heavier than Li.
 Very good sensitive for light elements.

14. Disadvantages/Limitation
 Analyzes conducting and semiconducting samples.
 Special procedure are required for non-conducting
samples.
 Only solid specimen can be analyzed.
 Samples that decompose under electron beam irradiation
cannot be studied.
 Hydrogen and helium are not detectable as they have
electron less than three.

15. Application :-
 Chemical shifts can be seen by Auger spectral peaks.
AES also throws light on the various oxidation states of
the elements.
 All elements except hydrogen and helium can produce
Auger spectra, in which the area under the peak is
measured to give a quantitative picture.
 AES is largely used for qualitative analysis of solid surface.
 AES is also use for depth profiling of surfaces.
 An Auger microprobe is used, to produce a beam that can
be moved across a surface.

16. References:-
 Chatwal G.R., Instrumental method of chemical analysis, 1st
edition, Himalaya Publishing house; 2004, page No. 3.18 – 3.21
 Banwell Colin N., Fundamentals of Molecular Spectroscopy, 4th
edition, McGraw Hill Education Private Limited; 2016, page
No.194-196
 Kaur H. , Spectroscopy , 28th edition, Pragati prakashan
2016, Page No. 643-646

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