Band alignment at InP/TiO₂ interfaces from density-functional theory

Abstract

The natural band alignments between indium phosphide and the main dioxides of titanium, i.e., rutile, anatase, and brookite as well as amorphous titania are calculated from the branch-point energies of the respective materials. Irrespective of the titania polymorph considered, type-I band alignment is predicted. This may change, however, in dependence on the microscopic interface structure: Supercell calculations for amorphous titania grown on P-rich InP(001) surfaces result in a titania conduction band slightly below that of InP. This agrees with recent experimental findings.