Monte Carlo simulation of the EBIC collection efficiency of a Schottky nanocontact

We have used a Monte Carlo (MC) algorithm to simulate the Electron Beam Induced Current (EBIC) collection efficiency of a nano-sized Schottky contact of radius r_c perpendicular to the incident electron beam. The surface area around the metallic contact was assumed to be an infinite recombination velocity. The results show that, at low beam energies, the EBIC collection efficiency increases rapidly as the radius of the contact (r_c) increases, and converges to a constant value as r_c becomes comparable to the carrier diffusion length. At higher beam energies, the variation of the EBIC signal with r_c is much slower because of the larger lateral extension of the generation volume. It is also shown that the maximum collection efficiency increases with the increase of the carrier diffusion length, and decreases as the incident beam energy increases, regardless of the size of the contact.