Density-Functional Study of the Electronic Structure and Optical Properties of Transparent Conducting Oxides In4Sn3O12 and In4Ge3O12

Abstract

The electronic structure and optical properties of In4Sn3O12 and In4Ge3O12 are studied by the projector-augmented-wave method based on the density-functional theory within the generalized gradient approximation. The cation ordering of the two compounds is explored by means of first-principles calculations. It is found that the valence-band maximum of the materials is determined by the d states of metal elements and O-2p states; the conduction-band minimum is occupied by an admixture of the O-2p states, In-5s states, and Sn-5s or Ge-4s states, respectively. The two compounds are direct-bandgap semiconductors. The low intensity of the absorption coefficient, reflectivity, and loss function shows that they are good transparent conducting oxides.