Structural, electrical and optical properties of InGaZnO4 and In29Sn3O48: a first-principles study

摘要

First-principles calculations were performed to investigate the electrical and optical properties of In29Sn3O48 with Sn-doped In2O3 and InGaZnO4 (IGZO). The band structure, density of states, optical properties including dielectric function, loss function, reflectivity and absorption coefficient are calculated. The calculated total energy shows that the most stable crystal structures are type III for In29Sn3O48 and type II for InGaZnO4. The band structure indicates the both In29Sn3O48 and InGaZnO4 are direct gap semiconductors. The intrinsic band gap of In29Sn3O48 is much narrower than that of InGaZnO4, and results in a better electrical conductivity for In29Sn3O48. The density of states shows the main hybridization occurring between In-4d and O-2p states for In29Sn3O48 while between In-4d In-5p, Zn-4s and O-2p states for InGaZnO4 near the valence band maximum. The reflectivity index R(omega) shows that the peak value of In29Sn3O48 and InGaZnO4 appears only in the ultraviolet range, indicating that these two materials have all excellent transparency. In addition, the absorption coefficient alpha(omega) of both In29Sn3O48 and InGaZnO4 is high in the ultraviolet frequency range, and therefore they show, a high UV absorption rate.