Nanoprobe Network

AES

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Current revision as of 05:02, 14 February 2011

Introduction

Auger Electron Spectroscopy (or AES) was discovered by Pierre Auger in 1925 when he was working with X rays and was using a Wilson Cloud Chamber. AES has become one of the most used techniques for obtaining chemical compositions of solid surfaces. AES has a high sensitivity for chemical analysis, rapid data acquistion speed,the abilty to detect all elements above helium, and a capability of high-spatial resolution. The high-spatial resolution comes from the specimen being excited by an electron beam focused into a fine probe. AES is generally used to identify elements on the surface of materials, determine the chemical states of elements, quantitatively determine elements on surfaces, among other things.

Advantages

The main advantage to using AES is that it has high spatial resolution, allowing it to identify fine features on the surface that might go unnoticed by substitute methods like X-ray photoelectric spectroscopy. AES is also highly sensitive to light elements, which allows it to easily detect them.

Disadvantages

Auger Electron Spectroscopy scans down to a depth of only five monolayers, which requires the scanned surface to be very clean. In addition, it is difficult for AES to detect isolated elements if the substrate surface contains multiple elements. AES also has difficulty studying insulators as a result of surface charging. Surface charges can change the yield of electrons that are emitted from the sample. The substrate surface is also at risk of being damaged by the electron beam.

Citations:

1) Handbook of Analytical Chemistry, (Prentice Hall, 1997), Chapter 42, pp. 791-808

2) Auger Electron Spectroscopy, (Surface Science, 1971), pp. 53-79