Thermoelectric Properties of Solid-State Synthesized Magnesium Silicides Doped with Group B<sup>I-III</sup> Elements

Abstract

Group BI(Cu, Ag)-, BII(Zn)- and BIII(Al, In)-doped Mg2Si compounds were synthesized by solid state reaction and mechanical alloying. Electronic transport properties (Hall coefficient, carrier concentration and mobility) and thermoelectric properties (Seebeck coefficient, electrical conductivity, power factor, thermal conductivity and figure of merit) were examined. Mg2Si powder was synthesized successfully by solid state reaction at 773 K for 6 h and doped by mechanical alloying for 24 h. It was fully consolidated by hot pressing at 1073 K for 1 h. The electrical conductivity increased by doping due to an increase in the carrier concentration. However, the thermal conductivity did not changed significantly by doping, which was due to much larger contribution of the lattice thermal conductivity over the electronic thermal conductivity. Group BIII(Al, In) elements were more effective to enhance the thermoelectric properties of Mg2Si.