Influence of Doping on Structural and Thermoelectric Properties of AgSbSe2

A series of samples with nominal compositions of AgSb1−xSnxSe2 (with x = 0.0, 0.1, 0.2, and 0.3) and AgSbSe2−yTey (with y = 0.0, 0.25, 0.5, 0.75, and 1.0) were prepared. The crystal structure of both single crystals and polycrystalline samples was analyzed using x-ray and neutron diffractometry. The electrical conductivity, thermal conductivity, and Seebeck coefficient were measured within the temperature range from 300 K to 700 K. In contrast to intrinsic AgSbSe2, samples doped with Sn and Te exhibit apparent semiconducting properties (Eg = 0.3 eV to 0.5 eV), lower electrical conductivity, and higher values of the Seebeck coefficient for a small amount of Sn (x = 0.1). Further doping leads to decrease of the thermoelectric power and increase of the electrical conductivity. In order to explain electron transport behavior observed in pure and doped AgSbSe2, electronic structure calculations were performed by the Korringa–Kohn–Rostoker method with coherent potential approximation (KKR–CPA).