Electronic structural analysis of transparent In2O3-ZnO films by hard X-ray photoelectron spectroscopy

The electronic structural analysis of the conductive transparent films was carried out using bulk sensitive hard X-ray photoelectron spectroscopy (HAXPES). The In₂O₃-ZnO film has amorphous structure before and after annealed, and the conduction band spectrum around Fermi level showed the similar spectra with that of as-deposited amorphous In₂O₃ film. In these amorphous films, the conduction band minimum locates at the deeper level than the crystalline In₂O₃ film. The electronic state which comes from randomness of amorphous structure possibly exists around this level or below. These electrons are expected to act as scattering center. We concluded that the electron mobility depends on the density of this electronic state.