Electronic Structure and Optical Properties of N-Doped Anatase TiO2 by First-Principles Calculations

The electronic structure and optical properties of TiO2 doped with N were calculated by first-principles based on DFT. The band gap of TiO2 was studied after N doping. It is concluded that the band gap is decreased and TiO2 turns into direct semiconductor. The electrons transition from valence band to conduction band becomes more easily. It is also found that the static dielectric constants become smaller and the imaginary part, epsilon(2) is also affected.