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

et al.Tin Selenide (SnSe), a thermoelectric material of the chalcogenide family, has attracted tremendous interest in the past few years due to its unprecedented thermoelectric figure-of-merit, ZT, of 2.6. In this work we have carried out an experimental study of the impact of annealing on the thermoelectric properties of polycrystalline SnSe formed by cold-pressing un-doped SnSe powders with a Hall carrier concentration of 5.37 × 10 cm. The crystalline structure and morphology of the samples are characterized and properties, including electrical conductivity, Seebeck coefficient and thermal conductivity, are measured. It is found that thermal annealing has a large impact on both the microstructure and the thermoelectric properties. Notably, annealing leads to re-alignment of crystalline domains, increase in Seebeck coefficient by a factor of as much as 3, and increase in the electrical conductivity. A peak ZT of 0.11 was achieved at 772 K which is smaller than un-doped polycrystalline SnSe.We wish to thank: Universidad Diego Portales, through the support of the Semilla project, JSR and CMST through the support of the Spanish MINECO project nanoTHERM (Grant No. CSD 2010-0044), the ICN2 – Institut Catala de Nanociencia i Nanotecnologia, the Aerospace and Mechanical Engineering Department at University of Notre Dame, the Physics Institute and Engineering School of Pontificia Universidad Católica de Chile, and finally to the Research Center on Nanotechnology and Advanced Materials, CIEN-UC.Peer Reviewe