Intrinsic defects in α- Al 2 O 3 : structural and electronic properties

Abstract Due to their high dielectric constants and wide band gaps, Al 2 O 3 has become popular in semiconductor applications, but with high-density interface defect structures. Understanding the structural distortions of intrinsic defects and their impact on electronic properties, is of particular importance for the applications. Herein, we study the impacts of four intrinsic defects on the structural and electronic properties of α - Al 2 O 3 using first-principles calculations. The four intrinsic defects cause structural distortions at their respective defect sites and defect states within the band gap, with O i inducing the most significant distortions and exhibiting the most complex defect states accordingly. When the Fermi level is 3.05 eV under O-poor conditions, V O is the most favorable defects based on the formation energy calculations. Additionally, the intrinsic defects in α - Al 2 O 3 can effectively modulate band edges, and thus modify the leakage currents. In summary, our results provide significant theoretical insights for α - Al 2 O 3 -based semiconductor applications.