Spectral Auger electron spectroscopy

Auger electron spectroscopy is preferred over XPS where high spatial resolution is required, although the samples need to be conducting and tolerant to damage from the electron beam. Many oxides readily decompose under electron radiation, and this may give rise to difficulty in spectral interpretation, and this has restricted the application of AES in the field of catalysis. 

The films and devices were characterized by inductive-coupled plasma spectrometry (ICP), Auger electron spectroscopy (AES), X-ray diffraction, electron-probe microanalysis (EPMA), current-voltage characteristics, and spectral response. 

Atomic absorption spectroscopy (AAS) is used to determine the chemical composition of the metal loading of a supported catalyst. In a sample preparation procedure the catalyst is treated with very strong and often oxidizing acids to extract all metal atoms as ions in solution. This solution is injected into a spectrometer that gives a quantitative analysis of all metal components in the solution based on the spectral absorption (or emission in the case of Auger electron spectroscopy, AES) in a flame. Note that in this method all dissolvable metal atoms are analyzed not only the catalytic active surface atoms. 

NIST X-ray Photoelectron Spectroscopy Database http //srdata.nist. gov/xps/. 2007. Database of many core photoelectron and Auger-electron spectral lines, currently containing over 22,000 entries. Free access. 

NEXAFS is a synchrotron-based spectroscopic tool routinely used as a complementary technique with XPS for surface characterizations. This method probes the adsorption of X-rays by the excitation of core (K-shell) electrons into unoccupied electronic states near the ionization limit. Subsequent emission of Auger electrons results in the formation of an NEXAFS electron yield the observed spectmm. Because the source of Auger electrons can extend only up to 10 nm and the spectral peak positions and intensities are directly related to the nature of unoccupied electronic states, NEXAFS spectroscopy provides an important tool for studying stmctural and chemical features of various surface thin films and coatings (Hemraj-Benny et al., 2006 Hahner, 2006). 

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