Conventional Auger electron spectroscopy

PAES (positron annihilation Auger electron spectroscopy) is another technique for producing true AES peak shapes that are free of the secondary electron background. PAES is identical to conventional Auger electron spectroscopy except that the sample excitation is done with a low energy beam of positrons rather than a higher energy beam of electrons. 

Accompanying the photoemission process, electron reorganisation can result in the ejection of a photon (X-ray fluorescence) or internal electronic reorganisation leading to the ejection of a second electron. The latter is referred to as the Auger process and is the basis of Auger electron spectroscopy (AES). It was Harris at General Electric s laboratories at Schenectady, USA, who first realised that a conventional LEED experiment could be modified easily to... 

We next discuss x-ray absorption studies. To put matters in context, it is useful to understand that conventional studies using Auger electron spectroscopy (AES) and x-ray photoemission spectroscopy (XPS) can be carried out only ex situ in high vacuum after electrochemical treatment since the techniques involve electron detection. X-ray absorption spectroscopy can, in contrast, be used for valence and structural environment studies. As x-rays only are involved, they can be carried out in situ in an electrochemical or similar cell. 

However, it seems that the use of the combined electrochemical pre-chamber/UHV main chamber device seems to be the best for these treatments. One of the methods consists of applying the same treatment to platinum single crystals for separate experiments. For characterization, low-energy electron diffraction, Auger electron spectroscopy, or XPS was used. Conventional electrochemical experiments were followed with the analysis of the results by taking into account the effect of the unavoidable differences in the required conditions. 

True peak shapes for Auger electron spectroscopy (AES) or X-ray photoelectron spectroscopy (XPS) that are free from the backgrounds, overlapping peaks and satellite features that are present in conventional AES or XPS are obtained. 

Fig. 7.1. Schematic diagram of the TOF-ESD microscopy system, termed the protoscope . A pencil-type electron gun for SEM and conventional low energy electron diffraction (LEED) gun for LEED, Auger electron spectroscopy (AES), and (electron stimulated desorption ion angular distribution (ESDIAD) are combined with an ion detector consisting of microchannel plates (MCPs) and a phosphor screen.

Examples of conventional instrumentation used for electron-excited X-ray emission spectroscopy and Auger electron spectrometry are shown in Figures 2 and 3 respectively. Details concerning the instrumentation may be found elsewhere (25-29). 

The third type of spectrometer, which uses retarding grids and electronic differentiation for energy analysis, is rather uncommon in conventional photoelectron spectroscopy. The reader is referred for further details to texts on LEED and Auger spectroscopy. 

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