Band offset measurements of the pulsed-laser-deposition-grown Sc 2O3 (111)/GaN (0001) heterostructure by X-ray photoelectron spectroscopy

Abstract

The energy band alignment of the Sc2O3/GaN heterointerface has been studied by means of X-ray photoelectron spectroscopy. The single-crystalline Sc2O3 was grown epitaxially on GaN template using pulsed laser deposition. A valence band offset of 0.84 ± 0.05 eV has been obtained across the heterointerface by using Ga 3d and Sc 3p energy core levels as the references. Given the bandgaps of 3.42 and 6.3 eV for GaN and Sc2O3, respectively, the conduction band offset has been estimated to be 2.04 eV in this system. These large band offsets are desirable, especially for GaN-based electronic devices, which are most suited for high-temperature operations, where the carrier thermionic emission must be maintained at a sufficient low level. © 2007 WILEY-VCH Verlag GmbH & Co. KGaA.