Thermoelectric properties of Bi-doped Mg2Si1−xSnx prepared by mechanical alloying

Bi-doped Mg2Si1−xSnx solid solutions were prepared by mechanical alloying and hot pressing. The lattice constant increased and the electrical conduction behavior changed from n-type to p-type with increasing Sn content. The electrical conductivity increased with increasing Sn content at a specific temperature. Bi-doped Mg2Si1−xSnx solid solutions showed n-type conduction, and the carrier concentration was increased because of doped Bi acting as donors. The absolute value of the Seebeck coefficient decreased with increasing temperature. The lowest thermal conductivity of 1.3–1.5 W/mK was obtained by Bi doping. Mg2Si0.7Sn0.3:Bi0.01 exhibited a maximum figure of merit (ZT) of 0.65 at 823 K.