Metallization and Schottky-barrier formation

Abstract

Results of self-consistent electronic-structure calculations aluminum deposited on Ge, as a function of metal coverage, provide strong evidence for overlayer metallization. At monolayer metal coverages, the overlayer changes into a (quasi-) two-dimensional metal characterized by a (modulated) ladder-type density of states. The origin of this transition is traced to the metal-semiconductor interlayer-distance relaxation upon metallization. Our results are in agreement with recent experimental observations, and have important implications for Schottky-barrier formation.