Band alignment at epitaxial SrTiO3–GaAs(001) heterojunction

Abstract

Band discontinuities and band bending at the epitaxial ${\mathrm{SrTiO}}_3∕\mathrm{GaAs}\left(001\right)$ interface were investigated using x-ray and ultraviolet photoelectron spectroscopy. Results showed that the epitaxial ${\mathrm{SrTiO}}_3∕\mathrm{GaAs}\left(001\right)$ formed a type II heterojunction with conduction and valence band offsets being 0.6 and 2.5 eV, respectively, for both $n$ - and $p$ -GaAs(001) substrates. The photoemission results further revealed that Fermi level was unpinned at the epitaxial ${\mathrm{SrTiO}}_3∕\mathrm{GaAs}\left(001\right)$ interface.