Thermodynamics of native defects in In2O3 crystals using a first-principles method

Abstract

The stability of the intrinsic point defects in bixbyite In₂O₃, including oxygen vacancies, oxygen interstitials, indium vacancies and indium interstitials, under a range of temperatures, oxygen partial pressures and stoichiometries has been studied by computational methods. The calculated results indicate that the a-position is not a suitable site for interstitials and both the b-position and d-position are favorable for indium vacancies with similar defect formation energies. Both donors (oxygen vacancies and indium interstitials in the c-position) and acceptors (indium vacancies in the b/d-position and oxygen interstitials in the c-position) are predicted to have shallow defect transition levels. Then defect formation energies of all possible charged states are used in thermodynamic calculations to predict the influence of temperature and oxygen partial pressure and varied Fermi level in a limited area on the relative stabilities of the point defects. The combined formation energies of point defect complexes, including Frenkel pairs, anti-Frenkel pairs and Schottky pairs, are calculated to predict relative stability in the paper.