Thermoelectric properties of Zn–Sb alloys doped with In

Abstract

Several samples of Zn–Sb alloys were prepared by doping with different amount of In (0, 5, 10 and 15 at%) using cold-pressing and sintering techniques. The X-ray powder diffraction patterns reveal that In-doped samples are complex phase mixture, which consist of β-Zn 4Sb 3 as the main phase and ZnSb, InSb and In as secondary phases. The thermoelectric properties for these alloys were studied by means of thermal and carrier transport measurement in the temperature range between 40 and 700 K. For all studied samples, the Seebeck coefficients were found to be positive in whole the temperature range under investigation. It suggests that the hole-type carriers dominate the thermoelectric transport. Temperature dependence of electric resistivity, Seebeck coefficient and thermal conductivity for these alloys were analyzed. From the experimental analysis, the indium doping in Zn–Sb alloys leads to an increase in Seebeck coefficient and electric resistivity and leads to a decrease in thermal conductivity of β-Zn 4Sb 3-based materials. The dimensionless figure of merit, ZT for these alloys were evaluated and discussed. It was found that the sample with 10 at% indium doping exhibits a larger figure of merit in the 40–700 K temperature range.