Unpinned Schottky barrier formation at metal–GaP interfaces: A representative III–V compound interface

Abstract

Metal–semiconductor interfaces obtained by deposition of In, Al, Cu, Ge, and Au onto ultrahigh-vacuum cleaved GaP surfaces have been studied by photoemission with synchrotron radiation. The results indicate a wide range of Schottky barrier height. A plot of the Schottky barrier values versus metal work function reveals an almost ideal Schottky-like behavior. Among current alternative models of metal–semiconductor interfaces, only the effective-work-function model is compatible with the experimental data. The GaP data plus the absence of Fermi level pinning recently observed for In-based semiconductors indicate that GaP may be more representative than GaAs of metal/III–V compound interfaces in general.