Solid-State Synthesis and Thermoelectric Properties of Mg2Si0.5Ge0.5Sbm

Mg2Si0.5Ge0.5Sbm (m = 0, 0.005, 0.01, 0.02, and 0.03) solid solutions were synthesized by a solid-state reaction and consolidated by hot pressing. All specimens showed n-type conduction, and carrier concentrations were increased from 4.0 × 1017 cm−3 to 3.2 × 1021 cm−3 by Sb doping. The electrical conductivity remarkably increased with increasing Sb doping content, but the absolute value of the Seebeck coefficient was reduced as the Sb doping content increased, which was attributed to the increased carrier concentration. The lowest thermal conductivity was 2.3 W/mK for Mg2Si0.5Ge0.5Sb0.02 at 723 K, and the maximum ZT value of 0.56 was obtained for Mg2Si0.5Ge0.5Sb0.02 at 823 K.