Effect of the annealing on the power factor of un-doped cold-pressed SnSe

Abstract

Tin Selenide (SnSe), a thermoelectric material of the chalcogenide family, has attracted tremendous interestin the past few years due to its unprecedented thermoelectric figure-of-merit, ZT, of 2.6. In this workwe have carried out an experimental study of the impact of annealing on the thermoelectric properties ofpolycrystalline SnSe formed by cold-pressing un-doped SnSe powders with a Hall carrier concentration of5.37×1017 cm3. The crystalline structure and morphology of the samples are characterized and properties,including electrical conductivity, Seebeck coefficient and thermal conductivity, are measured. Itis found that thermal annealing has a large impact on both the microstructure and the thermoelectricproperties. Notably, annealing leads to re-alignment of crystalline domains, increase in Seebeck coefficientby a factor of as much as 3, and increase in the electrical conductivity. A peak ZT of 0.11 wasachieved at 772 K which is smaller than un-doped polycrystalline SnSe.