Nature of the Band Gap of In2O3 Revealed by First-Principles Calculations and X-Ray Spectroscopy
Abstract
Bulk and surface sensitive x-ray spectroscopic techniques are applied in tandem to show that the valence band edge for In2O3 is found significantly closer to the bottom of the conduction band than expected on the basis of the widely quoted bulk band gap of 3.75 eV. First-principles theory shows that the upper valence bands of In2O3 exhibit a small dispersion and the conduction band minimum is positioned at Γ. However, direct optical transitions give a minimal dipole intensity until 0.8 eV below the valence band maximum. The results set an upper limit on the fundamental band gap of 2.9 eV.
- Publication:
-
Physical Review Letters
- Pub Date:
- April 2008
- DOI:
- Bibcode:
- 2008PhRvL.100p7402W
- Keywords:
-
- 78.70.En;
- 73.20.At;
- 78.20.Bh;
- X-ray emission spectra and fluorescence;
- Surface states band structure electron density of states;
- Theory models and numerical simulation