First-principles study of CuAlS₂ for p-type transparent conductive materials

Abstract

We have investigated the intrinsic defects, and Mg, Zn impurities in CuAlS 2 , as well as their induced carrier concentrations using the first-principles calculations. We find that p-type conductivity could be dominated by the intrinsic defects V Cu , Cu Al or the doping defects Zn Al , Mg Al in different samples. Although vacancy Cu is an important acceptor in CuAlS 2 , a Cu-deficient sample is not the best for p-type conductivity due to the compensation from Al Cu defects. In fact, our results indicate that Zn is the best choice for p-type doping for CuAlS 2 , in particular under Cu-rich and Al-poor condition, which is in line with the experimental results. The main difference in carrier concentration between theory and experiment is expected to have originated from the multiphase of the samples prepared in experiments, instead of a single crystal. We also find that there is no remarkable difference in the effective mass in samples dominated by different defects, such as Cu Al , Mg Al , Zn Al and Cu vacancy. The significant difference in the experimentally observed hole mobility may be dominated by their mean free time τ p .