Electronic structure of oxygen vacancy in crystalline InGaO3(ZnO)m

We perform first-principles theoretical calculations to investigate the defect properties of oxygen vacancy (V-O) in crystalline InGaO3(ZnO)(m) (m = 3). In a flat boundary structure, in which Ga atoms are located on a single plane, various configurations of V-O exist. We find that neutral V-O at a site near the In-O layer or in the ZnO area is energetically more favorable than those formed near and on the Ga-O layer. Although the defect levels vary with the type of metal ions in the neighborhood, V-O defects act as deep donors, similar to that of bulk ZnO. Moreover, the O-vacancies exhibit the negative-U behavior, with the charge transition levels well below the conduction band minimum. (C) 2009 Elsevier B.V. All rights reserved.