Carrier control in CuAgSe by growth process or doping

Abstract

CuAgSe is a promising thermoelectric material whose p-type and n-type thermoelectric figure of merit, ZT, values are relatively high (0.95 and 0.70, respectively). It exhibits native n-type conduction, while p-type conduction is present in non-stoichiometric CuAgSe. Here, we report that the carrier type in CuAgSe semiconductors can be effectively controlled by changing the growth process or doping. We were able to switch the carrier type of CuAgSe from the native n-type to the non-stoichiometric p-type by increasing the soaking time during growth. In contrast, the n-type conduction was always observed when Ni, Co, and Zn were doped into the host lattices. We obtained a maximum ZT value of 0.69 at 623 K in undoped n-type CuAgSe. Zn is a promising dopant for n-type CuAgSe with a ZT value of 0.68 at 623 K, which can be further optimized. Our work provided a simple and effective technique for producing both single-phase n- and p-type CuAgSe.