SnSe: Breakthrough or not breakthrough?

Abstract

The simple binary semiconductor SnSe has not been for long considered as a promising thermoelectric material compared to PbSe. For this reason, its thermoelectric properties have been largely overlooked over the past decades. This compound came back to the forefront of research in thermoelectricity due to very high thermoelectric figure of merit ZT values reported recently in single crystals. This announcement has been the starting point of renewed interest leading to a wealth of experimental and theoretical studies in the past few years with the aim of better understanding its physical properties and optimizing its thermoelectric performances in both p- and n-type samples. Here, we review the progress of research on transport properties of both single-crystalline and polycrystalline SnSe, highlighting in particular the controversy regarding thermal properties of single crystals and important points that remain to be investigated to determine whether or not the (re) discovery of SnSe may be considered as a breakthrough in thermoelectricity.