Valence band offsets for ALD SiO2 and Al2O3 on (InxGa1-x)2O3 for x = 0.25-0.74

Abstract

The incorporation of In2O3 into Ga2O3 allows for tailoring of the bandgap over a wide range in (InxGa1-x)2O3, and this material is emerging as a candidate in transparent electrodes on optoelectronic devices, heterostructure transistors, photodetectors, and gas sensors. We have measured the band alignments for atomic layer deposited SiO2 and Al2O3 over the composition range x = 0.25-0.74 for (InxGa1-x)2O3 grown by pulsed laser deposition. The valence band offsets from 1.95 to 2.30 eV for SiO2 and 0.88 to 1.23 eV for Al2O3 over this composition range. The bandgaps of (InxGa1-x)2O3 spanned from 4.55 to 4.05 for x = 0.74-0.25. This led to nested band alignments for SiO2 and Al2O3 for the entire composition range of (InxGa1-x)2O3 investigated.