Energy-band alignments at LaAlO3 and Ge interfaces

Abstract

The energy-band alignments for LaAlO3 films on p-Ge(001) with and without GeOxNy interfacial layer have been studied using photoemission spectroscopy. The valence-band offsets at LaAlO3∕GeOxNy∕Ge and LaAlO3∕Ge interfaces were measured to be 2.70 and 3.06eV, respectively. The effect of interfacial GeOxNy layer on the band alignments is attributed to the modification of interface dipoles. The conduction-band offsets at LaAlO3∕Si(001) and LaAlO3∕Ge interfaces are found to have the same value of 2.25±0.05eV, where the shift of valence-band top accounts for the difference in the energy-band alignment at two interfaces.