Oxygen Vacancies in Α-(Al X Ga1−x )2O3 Alloys: a First-Principles Study

alpha-(Al x Ga1-x )(2)O-3 alloys have attracted increasing interest as semiconductors with tunable wide band gaps. We report a systematic analysis of O vacancies in alpha-Al2O3, alpha-Ga2O3, and alpha-(Al x Ga1-x )(2)O-3 alloys using first-principles calculations. The formation energies and electronic levels of the O vacancies are sensitive to not only the nearest-neighbor Al/Ga ratio but also the atomic relaxation around the vacancies. Consequently, the vacancy formation energies vary by up to similar to 2 eV, reflecting diverse local atomic environments in the alloys. These results provide insight into further understanding and controlling the properties of alpha-(Al x Ga1-x )(2)O-3 alloys.