The inelastic mean free path of electrons in some semiconductor compounds and metals

Abstract

The elastic backscattering probability P, of electrons is proportional to the product of the inelastic mean free path (IMFP), effective backscattering cross section (a,,), and atomic density (N). Thus, experimental evaluation of P,, e.g. from the elastic peak intensity measurements, enables the determination of the IMFP. a,, can be calculated by integrating the differential elastic scattering cross sections using a simplified model based on the first Born approximation and the ThomasFermi-Dirac atomic potential. No significant difference in the values of a,, was found using the ThomasFermi, the Thomas-Fermi-Dirac and the HartreeFock atomic potentials or integrating the scattering cross sections tabulated by Fink ef al. From the experimental values of Pe reported by Schmid et al. and by Gergely the IMFP was determined for a number of elements. A good agreement was found with the data on the IMFP published in the literature. Comparing the elastic peak of two samples and using the data of Ashley and Tung as reference values, the IMFP has been determined for Gap, GaSb, InP, InSb and Si,N, samples. Good agreement with the data of Ashley and Tung was obtained for Si, Ge, Si02 and GaAs.

Evaluation of electron inelastic mean free paths for selected elements and compounds

“…4,12 With this technique, IMFPs can be determined from the elastic reflection coefficient (in a particular direction) for an electron beam of particular energy incident on a surface. It was convenient in most of these experiments to measure ratios of reflection coefficients that have been determined for the specimen material of interest and a selected reference material (with known IMFP) under identical experimental conditions.…”

Application of elastic peak electron spectroscopy (EPES) to determine inelastic mean free paths (IMFP) of electrons in copper and silver

“…Using such a method of measurement, one obtains qe in the form : q e = Iel/('p '1 (9) where T is the analyser transmission measured separately.…”

The Inelastic Mean Free Path οf Electrons. Research in Budapest, Warsaw, Wrocław and Clermont-Ferrand. Brief History and New Results

“…It is now a well known procedure to determine λ i from the elastic peak intensity. This was started by Jablonski et al in 1984 [6], and the research was continued permanently. EPES proved to be a practical tool for experimental determination of the IMFP.…”

“…CMA experiments were started in Budapest [6], composing the elastic peak intensity ratio I e,sample /I e,ref for the sample and selected reference materials like Al, Ni, Cu, Si, etc., thus the problems of T r (E) and R(E) were eliminated. The IMFP of the reference sample applied the NIST calculated TPP-2M values.…”