Effects of chalcogen substitution on electronic properties and chemical bondings of delafossite CuAlO2

Due to its p-type conductivity, CuAlO2 has been widely studied. However, the conductivity of p-type CuAlO2 is much lower than that of n-type, which limits its applications. We used the generalized gradient approximation and hybrid functional B3LYP to study the effects of chalcogen substitution on the electronic properties and chemical bondings of delafossite CuAlO2. The calculated results show that the doping of chalcogen (S, Se, and Te) substituting for O is thermodynamically stable. The calculated volumes, bandgaps, and valence-band widths of dopants have been detailedly discussed, indicating that the volumes and valence-band widths are increased, but the bandgaps are decreased. The density of states and charge-density distribution ranges have been analyzed, suggesting that chalcogen substitution is a good way to design new p-type Cu-based TCOs. (C) 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim