Effect of Er doping on the electronic structure and optical properties of ZnO

ZnO has a significant advantage for applications in optical devices. Especially ZnO doped with the rare earths (RE) shows great electronic and optical properties. Based on the density functional theory, using the first-principles calculations method, the crystal structure, electronic structure and optical properties of ZnO doped with various concentrations of Er were investigated. The calculated results show that with the increase of concentrations of Er, the volume of ZnO system is expanded. Simultaneously, the band gap of ZnO with dopant system becomes broad. However, the conductivity of system is enhanced with the decrease of Er concentration. On the other hand, imaginary part of the dielectric function of ZnO doped with Er also changes certainly. A new peak is observed in the low energy region. The results are helpful to gain a systematic understanding of geometrical structures, electrical structures and optical properties of Er-doped ZnO.