Surface point defects and Schottky barrier formation on ZnO(101̄0)

Abstract

We have created well-defined concentrations of surface point defects (oxygen vacancies, Vos) on ZnO(101̄0) surfaces under controlled UHV conditions and have tested their influence on Schottky barrier formation. ZnO(101̄0) with and without surface defects exhibit almost identical Schottky barrier features, independent of the evaporated metal. Surface work function and band bending variations with metal coverage are qualitatively different for Au vs Al interfaces, regardless of defect concentration. Barrier formation occurs relatively slowly for Au on ZnO, while Al on ZnO induces a pronounced dipole with the first half monolayer.