Valence and conduction band offsets in AZO/Ga2O3 heterostructures

We report on the determination of band offsets in rf-sputtered Aluminum Zinc Oxide (AZO)/single crystal β-Ga2O3 (AZO/Ga2O3) heterostructures using X-Ray Photoelectron Spectroscopy. The bandgaps of the materials were determined by Reflection Electron Energy Loss Spectroscopy as 4.6 eV for Ga2O3 and 3.2eV for AZO. The valence band offset was determined to be −0.61eV ± 0.23eV, while the conduction band offset was determined to be −0.79 ± 0.34 eV. The AZO/Ga2O3 system has a nested, or straddling, gap (type I) alignment and provides a convenient method for reducing contact resistance on Ga2O3-based device structures.