Investigation of thermoelectric properties of chalcogenide semiconductors from first principles

Abstract

In recent years, thermoelectric (TE) materials have attracted increasing interest due to their potential use in energy harvesting and conserving applications. A particular research effort has been focused on developing new materials with high ZT values, which are essential for TEs to be commercially applicable in refrigeration and waste heat recovery. Several promising bulk semiconductors have been reported by researchers so far. However, no satisfactorily high ZT value has been obtained. In a recent publication, [E. J. Skoug et al., Appl. Phys. Lett. 96, 181905 (2010)] reported very low lattice thermal conductivity on chalcogenide semiconductors and pointed out their potential for thermoelectricity. Following their findings, transport properties of these materials and some other promising bulk semiconductors, Bi2Te3, SrTiO3, and Cu2ZnSnSe4, were systematically analyzed using density functional and Boltzmann transport theories. In order to assess their capacity as thermoelectrics, a simple measure: ‘maximum’ thermoelectric figure of merit, ZTm, was predicted at experimentally amenable doping levels. Results with higher ZTm values were obtained when compared to the current state of bulk thermoelectric materials. However, it is also found that reaching required ZT values for commonplace device applications with either these chalcogenides or the other semiconductors reported in our study is highly unlikely.