Elastic peak electron spectroscopy for auger electron spectroscopy and electron energy loss spectroscopy

Abstract Elastic peak electron spectroscopy deals with the spectra of secondary electrons in the neighbourhood of E p primary energy and determines them in absolute units based on the N e percentage of elastically reflected electrons. A procedure is described for evaluating elastic peak spectra. Experimental results on graphite, Si, Ge, stainless steel, Mo, W and Au polycrystalline samples are presented in the medium energy ( E p = 1–3 ke V) range. Spectra were measured with a cylindrical mirror analyser operated in the direct current mode. For elements (Si, Mo, etc.) N e is determined mainly by the atomic number Z , N e (Z)∼( Z – 26) 0.65 was found for Z ≥ 26 and E p = 3.1 ke V. The E p dependence of N e can be approximated by a power law N e ( E p )∼ E p −β(Z) , with β( Z ) varying between 2 and 0.4 for the Z = 4–79 atomic number range. The elastic peak is composed of electrons escaping from a surface layer determined by the inelastic mean free path of primary electrons. Using Seah's values and from the N e experimental data the backscattering cross‐sections were determined. They varied between 5 × 10 −20 (C)−2.8 × 10 −18 cm 2 (W, Au). Some new results are presented on the volume plasmon losses. In Si and Ge the mean free path of medium energy electrons is determined by the first volume plasmon loss, whereas in metals the contributions of other loss processes are important. It is practical to use the elastic peak and N e as references for Auger and loss peaks allowing the estimation of ionization cross‐sections in Auger electron spectroscopy.