GGA + U method study on optical properties of different concentrations of La (Z) and nitrogen (N) doped wurtzite ZnO

In this paper, the GGA + U method based on density functional theory, is used to calculate the electronic structures and optical properties of pure ZnO, La doped, and N doped ZnO systems, and Zn_{1 - n} La_n O_0.875 N_0.125 (n = 0.125, 0.25, 0.375). The calculation results show that with the increase of La concentration in the co-doped system, the forbidden band width of the doped system becomes smaller, the energy required for electronic transition decreases, the lattice distortion is large, which is beneficial to hinder the composite of photogenerated holes and electron pairs, and the absorbing edge of the absorption spectrum redshifts more obviously, the absorption spectrum covering the entire visible region. These characteristics are very advantageous to illustrate that the photocatalytic and electrical properties of the co-doped systems are improved with the increase of La concentration. (authors)