Bulk and surface sensitive x-ray spectroscopic techniques are applied in tandem to show that the valence band edge for In(2)O(3) 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 In(2)O(3) exhibit a small dispersion and the conduction band minimum is positioned at Gamma. 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.
- sn-doped in2o3