Energy spectra of electrons quasi-elastically backscattered from solid surfaces

Abstract

The energy distribution of electrons quasi-elastically backscattered from solids has been investigated. Monte Carlo (MC) simulations were performed for the study of the recoil energy shift and the broadening of this distribution for backscattered electrons from Si and Au. In these simulations, electron interaction cross sections were obtained from calculations based on the dielectric response theory for inelastic interactions, including volume and surface excitations, and elastic interactions. The depth-dependent electron inelastic mean free path for volume excitations and the probability of surface excitations were calculated using the dielectric functions derived from optical data. The relativistic partial-wave expansion method was applied to calculate the elastic scattering cross section for a potential of the atom in the solid. The Rutherford-type recoil energy was included in the MC simulations by either considering or neglecting the thermal effect of atomic vibrations. Such an effect was applied using the single scattering model. The intensity of electrons quasi-elastically backscattered from Si and Au was simulated for incident electrons of an energy distribution. The adjustment for the spectrometer energy resolution was allowed. An analytic expression for the intensity of backscattered electrons by a single scattering was derived explicitly. A comparison of simulated results with experimental data was made and discussed.