Interplay between order and disorder in the high performance of amorphous transparent conducting oxides

We demonstrate, using first-principles calculations, that the exceptional behavior of amorphous transparent conducting oxides formed from In, Zn, Ga, and Al cations arises from the preservation of local crystal order in the cation centered polyhedra, which is maintained due to the strong charge transfer to oxygen. While tails of localized states may be created above the valence band, the highly delocalized conduction band remains unperturbed, offering effective n-type conduction despite the existence of long-range structural disorder. This is in direct contrast to the paradigm set by amorphous covalent semiconductors.