Ab initio study of atomic structure and Schottky barrier height at the GaAs / Ni 0.5 Pt 0.5 Ge interface

We report a study of the atomic and electronic structures of GaAs(001)/NiPtGe(001) interfaces. By using density functional theory, we study the dependence of the Schottky barrier on the interface stoichiometry. The calculated $p$-type Schottky barrier heights vary by as much as 0.18 eV around the average value of 0.5 eV, which corresponds to a strongly pinned interface. We relate the As-Ge bonds at the interface with a strong Fermi level pinning.