First-principle study on the effects of Tl doping on the band gap and the band-edge of optical absorption of InI

Abstract

According to the density functional theory, using first-principles plane-wave ultrasoft pseudopotential method, models for a pure InI and different concentrations of Tl-doped InI are set up, and the geomertry optimizations for the modes are carried out. The total density of states, the band structures and the optical absorption are also calculated. The results show that the smaller the doping concentration of Tl, the smaller the formation energy of InI is, thus the more stable the crystal structure is. The Tl doping causes the bottom of conduction band shift to a higher energy, while the location of the top of valence band has no change. This makes the band gap of InI broadened, and the absorption spectrum obviously blue-shifted.