In2O3 doped with hydrogen: electronic structure and optical properties from the pseudopotential Self-Interaction Corrected Density Functional Theory and the Random Phase Approximation

We discuss the applicability of the pseudopotential-like self-interaction correction (pSIC) to the study of defect energetics and electronic structure of In2O3. Our results predict that substitutional (at oxygen sites) and interstitial (at antibonding positions) hydrogen, as well as oxygen vacancies with charges +1 and +2, are stable configurations of defects in cubic In2O3; the former form shallow levels (only as substitutional defects), whereas the latter form deep levels. The band structure calculated with the pSIC shows an excellent agreement with experimental data. In particular, the gap for defect-free In2O3 is 2.85 eV, which compares fairly with the experimental range 2.3-2.9 eV. The pSIC results also point to a change from indirect to direct gaps depending on doping. In relation to the optical properties, obtained within the random phase approximation, it is shown that they are mostly affected by the presence of oxygen vacancies.