Oxygen vacancies in α-(Al x Ga1−x )2O3 alloys: a first-principles study

Abstract

Abstract α-(Al x Ga1−x )2O3 alloys have attracted increasing interest as semiconductors with tunable wide band gaps. We report a systematic analysis of O vacancies in α-Al2O3, α-Ga2O3, and α-(Al x Ga1−x )2O3 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 ∼2 eV, reflecting diverse local atomic environments in the alloys. These results provide insight into further understanding and controlling the properties of α-(Al x Ga1−x )2O3 alloys.