AUGER ELECTRON SPECTOSOPPY

INTRODUCTION• Auger Electron Spectroscopy (AES), is a widely

used technique to investigate the composition of surfaces.

• First discovered in 1923 by Lise Meitner and later independently discovered once again in 1925 by Pierre Auger.

LISE MEITNER PIERRE AUGER

PRINCIPLE OF OPREATION• sample bombardment by

electrons

• core electron removed

• electron from a higher energy level fall into the vacancy

• release of energy.

• measured energy and defined sample

INSTUMENTATION

• Elements of Typical Auger System: Electron Gun Analyzer Secondary Electron Detector Ion Gun Sample Stage Introduction System

AES INSTRUMENT

ADVANTAGES

• Elemental mapping across surface

• Elemental depth profiling with uniform sensitivity• Monolayer-sensitive surface analysis with high

spatial resolution

• It is sensitive to light elements (except H and He).

DISADVANTAGES

• Surface Sensitivity: < 1 nm

• Lateral Resolution: < 50 nm

• Analytical Volume: 10-18 cm3

• Insulators are difficult to study due to surface charging.

• Surface may be damaged by the incident electron beam.

APPLICATION

1) AES is used to monitor the elemental composition of surfaces during physical property measurements.

2) phenomena such as adsorption, desorption, surface segregation from the bulk, measurement of diffusion coefficients, and catalytic activity of surfaces have been investigated using AES.

3) It has also been used to study the surface compositional changes in alloys during ion sputtering.

4) Chemical properties such as corrosion, stress corrosion, oxidation, and catalytic activity and mechanical properties such as fatigue, wear, adhesion, resistance to deformation processes, and surface cracking depend on surface properties.

5) AES has been used to relate surface and grain boundary chemistry to properties of materials

SUMMARY

AES is very important analytical techniques used in materials science to investigate molecular surface structures and their electronic properties

REFERENCE

• Literature:• 1) Douglas A. skoog 2007 instrumental

analysis.• 2) Principle of instrumental analysis 5th edition

by skoog , holler and nieman publisher thomson

• WEBSITE: • http://www.orlabs.com/

AugerElectronSpectroscopy.php• http://www.wellesley.edu/Chemistry/Chris/

AES.html • http://www.Ism.rutgers.edu/esca/

principles.html • http://www.rci.rutgers.edu/.../LECTURE5

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