Determination of band alignment of pulsed-laser-deposited perovskite titanate/III-V semiconductor heterostructure using X-ray and ultraviolet photoelectron spectroscopy

Abstract

Techniques of X-ray and ultraviolet photoelectron spectroscopy are performed to investigate the energy band discontinuity of pulsed-laser-deposited SrTiO3 (STO)/GaAs heterostructure. The valence band offset is determined to be 2.6 eV, while the conduction band offset is deduced to be 0.7 eV. As a consequence, an energy band diagram of STO/GaAs with a type II band alignment forming at the interface is precisely constructed. The chemical states across the STO/GaAs interface are investigated by sputter-depth profile, and there are no detectable interfacial reaction and intermediate layer occurring between the epitaxial STO film and GaAs substrate.