Thermoelectric properties of p-type polycrystalline SnSe doped with Ag

Many IV-VI semiconductors tend to be good thermoelectric materials, these include all Pb chalcogenides as well as Pb-free SnTe: all of which crystallize in a NaCl cubic structure. Another group of IV-VI compounds form layered orthorhombic structures. SnSe is one of these compounds, whose transport properties as a polycrystalline thermoelectric material have rarely been studied. Here we present our study of p-type polycrystalline SnSe doped with Ag, prepared by melting and hot pressing. SnSe has anisotropic properties with hysteresis observed in resistivity between 300 and 650 K regardless of doping. Ag is not an ideal dopant but is able to increase the carrier density significantly, as a result a peak zT of 0.6 was observed at 750 K. Transport properties of doped SnSe can be explained with a single parabolic band model, which suggests promising potential for this compound together with its challenges.