Optoelectronic structure and related transport properties of BiCuSeO-based oxychalcogenides: First principle calculations

Abstract

Recent experiments have revealed that the p-type BiCuSeO-based oxychalcogenides compounds exhibit a high thermoelectric figures of merit due to their very low lattice thermal conductivities and moderate Seebeck coefficient in the medium temperature range. In the present work, we reported on the optoelectronic and thermoelectric properties using the full potential linear augmented plane wave method and modified Becke-Johnson potential with spin-orbit coupling. The properties show that the BiCuSeO-based oxychalcogenides exhibit a semiconductor behavior with band gap values of 0.51, 0.45 and 0.41 eV for BiCuSO, BiCuSeO, and BiCuTeO, respectively. Due to their prominent role for thermoelectric applications, we combined Boltzmann transport theory to DFT results to compute the transport properties, mainly electronic conductivity, thermal conductivity, Seebeck coefficient and power factor. The present results show the dominance of BiCuTeO for thermoelectric application compared to the BiCuSO and BiCuSeO.