Effect of boundary scattering on the thermal conductivity of a nanostructured semiconductor material based on the Bi x Sb2 − x Te3 solid solution

Abstract

This paper reports on a theoretical and experimental investigation of the behavior of the electrical and thermal conductivities of a nanostructured material based on BixSb2 − xTe3 solid solutions. The effect of boundary scattering has been taken into account by introducing the scattering mechanism with a constant mean free path equal to the nanoparticle size. A comparison with the results of the measurements has demonstrated that one can describe satisfactorily the experimental dependences of the electrical and thermal conductivities on the nanoparticle size by using only the parameters of the initial solid solution and its pure constituents. The estimates have revealed that the lattice thermal conductivity of nanostructured materials can be reduced by 20–30% as compared to the initial solid solution with nanoparticle sizes of the order of 20 nm, which should produce a favorable effect on the magnitude of the thermoelectric figure-of-merit.