First-principles calculations of electronic and optical properties of aluminum-doped β-Ga2O3 with intrinsic defects

Abstract In this manuscript, the effects of intrinsic defects on the electronic and optical properties of aluminum-doped β-Ga 2 O 3 are investigated with first-principles calculations. Four types of defect complexes have been considered: Al Ga2O3 V O (Al-doped β-Ga 2 O 3 with O vacancy), Al Ga2O3 V Ga (Al-doped β-Ga 2 O 3 with Ga vacancy), Al Ga2O3 Ga i (Al-doped β-Ga 2 O 3 with Ga interstitial) and Al Ga2O3 O i (Al-doped β-Ga 2 O 3 with O interstitial). The calculation results show that the incorporation of Al into β-Ga 2 O 3 leads to the tendency of forming O interstitial defects. And the bandgap of Al Ga2O3 is 4.975 eV, which is a little larger than that of intrinsic β-Ga 2 O 3 . When O vacancies exist, a defect energy level is introduced to the forbidden band as a deep donor level, while no defective energy levels occur in the forbidden band with O interstitials. After Al-doped, a slightly blue-shift appears in the intrinsic absorption edge, and an additional absorption peak occurs with O vacancy located in 3.69 eV.