Impurities effects on the electronic structure of titanium dioxide

Abstract

Effects of substitutional doping of nitrogen to TiO2 are studied within the framework of the density-functional theory (DFT). We compare the total energy and the electronic structure of pristine TiO2 with those of nitrogen-doped TiO2. It is found that the smaller the concentration of doped nitrogen is, the more energy is required for the substitutional doping of the nitrogen atom in both rutile and anatase phases. This result suggests that the doped nitrogen atoms tend to be clustered. A sizable reduction of the photoexcitation energy is also suggested in the rutile structure.