A GGA+U study of electronic structure and the optical properties of different concentrations Tb doped ZnO

In order to evaluate the electronic structure and optical properties of Tb-doped ZnO with various concentrations of Tb, we used the GGA + U method based on the first-principles method. Our calculations show that the idea of Tb-doped ZnO is feasible. The band gap of Tb-doped ZnO decreases and the Fermi level shifts upward. As the doping concentration increases (3.13%–6.25%), both the absorption peak and reflectance peak of the material decrease, and exhibit a red-shift. In the near-ultraviolet region from 240 to 380 nm, the absorption effect and the reflectivity of Tb-doped ZnO decrease with increasing Tb doping concentration. In the visible region, the absorption effect of Tb-doped ZnO is better than that of pure ZnO, but the reflectance is opposite. Thus, selecting a better doping level can make Tb doped ZnO exhibit better photoelectric properties. The research results can also provide a theoretical reference for subsequent researches of Tb-doped ZnO.