First-principles study on La-doped ZnO used as transparent electrode for optoelectronic device

A systematic study on electronic and optical properties of wurtzite zinc oxide (ZnO) with different Ladoping concentrations has been performed. The calculations are based on the first principles planewave pseudopotential method with the density functional theory (DFT) and the generalized gradient approximation (GGA). According to the results, the band gap of ZnO is broadened due to the increase of La-doping concentrations. By La-doping, the decrease of absorption coefficient and the blueshift of absorption edge are obtained. In addition, there is a strong interaction between the La atom and the surrounding atoms, because the high electron density overlaps. By Mulliken population analysis, we found out that the metallization effect appears due to the increase of La-doping concentration, which demonstrates that the La-doped ZnO is a potential material as a low absorption coefficient semiconductor material. The simulation and calculation results are in good agreement with the existing experimental data and the study can provide a theoretical basis for future applications of La-doped ZnO as a semi-transparent electrode.