Total Electron Yield (TEY) A New Approach for Quantitative X-ray Analysis

Abstract

An irradiation of solid samples with x-rays causes an electron emission from the sample surface, owing to photoabsorption. These electrons can be detected under vacuum conditions and are photo, Auger and secondary electrons. Due to inelastic collisions most of these electrons have lost some of their original kinetic energy along the path from the atom of origin to the surface. With nondispersive electron detection the total electron yield (TEY) is observed. For measurements performed with a tunable x-ray monochromator information on the qualitative composition can be obtained by the following procedure. The photon energy has to be timed from below to above of one of the absorption edges of a given element. In case of its presence in the specimen an increase of the TEY-signal can be observed.

Electron transport in solids for quantitative surface analysis

“…This assumption exactly matches the quasi-elastic or constant cross-section approximation. For a technique where all electrons leaving the target irrespective of their energy contribute to the signal, the appropriate absorption length is obviously given by the linear range R. This is exactly the case in the so-called total electron yield (TEY) technique, 3 where the difference in the total electron yield for incident photons with energies just above and below an absorption edge is taken as a measure for the concentration of a given species. Likewise, for most applications of electron microscopy, those electrons that have lost a considerable fraction of their original energy remain of interest because they still contribute to the signal generation process.…”

“…A technique for which the slowing down surface sensitivity is of paramount importance is the so-called total electron yield (TEY) technique. 3,106,107 Until recently, the question of which parameter determines the surface sensitivity had been unresolved. Some authors claimed that it is the linear range, 106 whereas others use the IMFP.…”

“…The same holds true for the normalized distribution of energy losses in a surface excitation. 3,16,188 (3) Absolute values of the surface excitation parameter have also been obtained in this way. It was shown that these follow the simple expression by Oswald 178 when rescaled by a material parameter.…”

“…This survey is not restricted to AES and XPS but also includes examples for techniques such as electron microprobe analysis (EPMA) 2 and total electron yield (TEY). 3…”

Quantitative analysis by X-ray induced total electron yield (TEY) compared to XRFA

“…For computations the thicknesses and compositions as given by the supplier of the Al x Ga 1−x As layers were used (Ebel et al , 1997; 1997; 1995; 1995; 2002). Further investigations on quantitative TEY were performed on the binary alloy systems Au–Cu (Ebel et al , 1995; 1995), Au–Pd (Ebel et al , 1997) and a basic contribution to quantitative TEY was made by Ghassemi (2003).…”