High Thermoelectric Figure of Merit and Nanostructuring in Bulk <i>p</i>-type Ge_<i>x</i>(Sn_<i>y</i>Pb_1−<i>y</i>)_1−<i>x</i>Te Alloys Following a Spinodal Decomposition Reaction

Abstract

The use of thermoelectricity for direct energy conversion from thermal to electrical energy has a long-standing history. We report that the complex p -type Ge(Sn,Pb,Te)Te alloys upon suitable alloying with SnTe can be designed to obtain very high ZT values of up to 1.2 because of both optimal electronic transport properties and minimal lattice thermal conductivity. Such alloys follow a spinodal decomposition reaction, leading to an ordered periodic nanostructure that is effective in the scattering of phonons and reduction of the lattice thermal conductivity.