Thermal conductivity reduction in GaSb1-xTex (0 ≤ x ≤ 0.12) thermoelectric materials

Abstract

XSb (X = Ga, In) based thermoelectric (TE) materials have received much attention due to the high electronic performance. However, the high lattice thermal conductivity limits further TE performance enhancement. In this work, GaSb1-xTex (x ≤ 0.12) compounds were prepared to investigate the effect of Ga vacancies induced by Te doping on the lattice thermal conductivity. The room temperature lattice thermal conductivity decreases significantly from ~24 Wm−1K−1 for GaSb to ~3.4 Wm−1K−1 for GaSb0.88Te0.12. The Callaway model was used to analyze the detailed phonon scattering mechanism. The effect of each scattering mechanism at different phonon frequencies and temperatures are investigated. The lattice thermal conductivity reduction due to vacancies combined with isoelectronic substitution is predicted. These results are of importance for further TE performance enhancement of the XSb (X = Ga, In) based TE materials.