A k-space transport analysis of the BEEM spectroscopy of Au/Si Schottky barriers

We address the question of the spatial resolution of ballistic electron emission microscopy (BEEM) of Shottky barriers in Au(111)/Si(100) and Au(111)/Si(111) interfaces. A novel combination of Green-function and k-space Ensemble-Monte-Carlo techniques is used to obtain new insights into the spatial and energetic evolution of the STM-tip-induced electrons during their passage through the metallic layer before reaching the metal-semiconductor interface. In particular, it is shown how the effect of band-structure-induced directional focusing of the electrons enforces a reinterpretation of existing experimental data.