Auger electron spectroscopy basic process

Of all the techniques that have been developed to analyze surfaces. Auger electron spectroscopy has had the most widespread application. In the field of materials science, it has joined such analytical methods as X-ray diffraction and transmission electron microscopy as a staple of any well-equipped laboratory. It is used in chemistry and materials science to study the composition of solid surfaces and the chemical states of atoms and molecules on those surfaces. Chemists and physicists study the basic Auger transition to help learn about electronic processes in solids. Those interested in developing electronic equipment have been concerned with providing spectrometers with ever-decreasing incident beam diameters that will allow the chemical analysis of a surface on a microscopic scale. It is hoped that this article plus the... 

The previous paragraphs give a brief introduction of the Auger process and the basic way in which surfaces are analyzed with it. However, the great power of Auger electron spectroscopy has been broad in its applicability. We now wish to discuss these applications in the field of materials science. 

While the same basic mechanisms for passivity of pure metals also applies to alloys, the processes involved in the passivation of alloys have an added complexity. In many cases only one component of the alloy has the property of being passive in a particular environment. Alloys such as steiinless steels, which contain highly passive components (chromium in this case), owe their corrosion resistance to the surface enrichment of the passivating component Thus stainless steels resist corrosion in many acidic systems (where iron or carbon steel would be poorly passive or not passive at all) by a passivating oxide film containing Cr predominantly as Cr(III). Surface analytical techniques such as Auger electron and X-ray photoelectron spectroscopies reveal substantial enrichment of chromium in the passivating oxide film on these alloys " . There are only two ways by which this enrichment can... 

NEXAFS spectroscopy basically does not require the most sophisticated apparatus to be performed but a source of tunable radiation as that dispensed by a photon factory or synchrotron plant. The experimental station for the study of macromolecular materials requires a UHV system and a detector apparatus for counting the emitted electrons. The primary process in NEXAFS is the core electron excitation into an appropriate final state empty molecular orbital. After excitation, the whole system undergoes relaxation and this can occur through two main decay processes secondary or Auger electron emission and fluorescence emission. Mostly, the detector for NEXAFS uses a simple channeltron tuned for a specific Auger energy or tuned to collect the whole secondary electrons resulting from the relaxation process fluorescence detector are also relatively common alternatively, for sample insulator the measurement of the drain current from the conductor sample holder is often measured examples are displayed in Fig. 4.4. Measurements can be performed on gas, solid and recently liquid state [3]. 

Tompkins (1978) concentrates on the fundamental and experimental aspects of the chemisorption of gases on metals. The book covers techniques for the preparation and maintenance of clean metal surfaces, the basic principles of the adsorption process, thermal accommodation and molecular beam scattering, desorption phenomena, adsorption isotherms, heats of chemisorption, thermodynamics of chemisorption, statistical thermodynamics of adsorption, electronic theory of metals, electronic theory of metal surfaces, perturbation of surface electronic properties by chemisorption, low energy electron diffraction (LEED), infra-red spectroscopy of chemisorbed molecules, field emmission microscopy, field ion microscopy, mobility of species, electron impact auger spectroscopy. X-ray and ultra-violet photoelectron spectroscopy, ion neutralization spectroscopy, electron energy loss spectroscopy, appearance potential spectroscopy, electronic properties of adsorbed layers. 

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