The study of electron emission from aluminum in the very low primary energy range using Monte Carlo simulations

The total electron emission yield (TEEY), at very low energy, is investigated with a Monte Carlo (MC) technique and compared with experimental results. The important points of an MC tool for the simulation of electron emission are presented. The tool is based on a combination of properly selected models taking into account plasmon excitations at the surface and the effect of the crossing surface-barrier potential. The reflectivity is calculated as a function of the primary energy using an analytical expression found in the literature. By comparing MC results with the measurements, a good correspondence between obtained curve shapes is observed. Irregularities in measured and simulated yields are identified and explained by considering plasmon excitations. This comparison allows one, among other things, to remove the ambiguity on the variation of the yield obeying the change in reflectivity as a function of primary energy. In fact, some results reported in the literature claim that the TEEY coefficient approaches unity when the primary electron energy tends to zero. This occurs due to nearly total electron reflection from the surface, for electron energy less than an electron volt. In this paper, we summarize comprehensive studies rendering this claim inaccurate. Aluminum, a free-electron-like metal, will be considered here as a representative illustration.