ABSTRACT
In this paper, density functional theory is used to investigate the effect of single doping and co-doping of Ce and N atoms at different concentrations on the electronic structure and optical properties of NOT system. The calculation results reveal that Ce concentration of 0.375 at% provides the best stability in the co-doped systems. Doping elements have a significant influence on the chemical properties of NOT and can lead to lattice distortion, which is beneficial for the separation of photogenerated electron-hole pairs. After doping, the band gap of the system is reduced. Consequently, the energy required for the electronic transition from valence band to conduction band is reduced, which causes a red shift in the absorption band edge. The absorption spectrum of the co-doped system appears in the visible range. When the Ce concentration in the co-doped system is 0.125 at% and 0.25 at%, a stronger absorption peak appears in the visible range, indicating that these two systems have the best response to visible light.
