Electron emission yield for low energy electrons: Monte Carlo simulation and experimental comparison for Al, Ag, and Si

The electron emission under electron impact between 10 eV and 2 keV is investigated with a Monte Carlo (MC) code in aluminum, silver, and silicon. The code is based on the complex dielectric function theory to describe the inelastic scattering and uses the Mott's model of partial waves to describe the elastic scattering. It takes into account both volume and surface plasmon excitations. The simulation results are compared with the experimental measurements of electron emission yields (EEY) and energy spectra of low energy electrons performed in ultrahigh vacuum on Ar-etched bulk samples. Our MC simulations at low energy are found to be in fairly good agreement with our experimental measurements. The peaks corresponding to the surface plasmon, the volume plasmon and its multiples and to the Auger transitions appear clearly on the energy loss spectra of aluminum, silver, and silicon. The simulated EEY are also in fairly good agreement with our measurements and with data from the literature. The EEY at normal incidence is studied for secondary and backscattered electrons. A focus is made for the EEY below 50 eV where a fairly good agreement is found with Bronstein and Fraiman's measurements on vacuum evaporated samples. Below 2 keV, for silver and aluminum, the total EEY is given for different angles of incidence h. Some discrepancies are observed between our experimental measurements and our MC simulations for high angles of incidence. These discrepancies can be attributed to the modeling of surface plasmon excitations, surface oxidation, or roughness that occur during the Ar-etching process. Published by AIP Publishing.