Study of optical properties of ZnO doped with Fe

Abstract

Using first-principles calculations based on density functional theory, we investigate the electronic structures and optical properties of ZnO doped by Fe with different positions. By analyzing the electronic structures and optical properties of the doped systems, we can theoretically analyze and predict the optical and electrical practical applications of Fe-doped ZnO semiconductors. By analyzing and comparing the densities of electronic states before and after doped, we can draw some conclusions. The conclusions show that the doping of impurities have influence on the lattice distortion of the system, and the distortion is benefit for the separation of photo generated hole-electron pairs. Therefore, the photocatalytic activity of the materials can be improved. Fe-3d states destroys the integrity of crystals and forms crystal fields around impurity atoms, which results in splitting of energy levels and narrowing of bandgap. Compared with intrinsic ZnO, the static dielectric constant of all doped systems decreases, which indicates that the polarization ability of the doped systems decreases. The main peaks of the dielectric function imaginary part of the doping systems move to the low energy region, and the absorption spectrums are red-shifted. In the visible region, the absorption capacity of the both doped systems increases, their response range is enlarged in turn, showing the doping of Fe is benefit for improving the photocatalytic activity of ZnO.