Band offsets in the Sc2O3∕GaN heterojunction system

Abstract

The Sc2O3∕GaN interface shows low trap densities and has been used both to demonstrate inversion in gated metal-oxide-semiconductor diodes and to mitigate current collapse in AlGaN∕GaN heterostructure transistors but little is known of the band offsets at this interface. We measured the energy discontinuity in the valence band (ΔEv) of Sc2O3∕GaN heterostructures using x-ray photoelectron spectroscopy. A value of ΔEv=0.42±0.07eV was obtained using the Ga 3d energy level as a reference. With the experimental band gap of 6.0eV for the Sc2O3 grown by this method, this implies that the conduction band offset ΔEC is 2.14eV in this system.