Lattice Deformation-Induced Enhancement in Thermoelectric Properties of p-Type Bismuth Telluride-Based Alloys

The properties of a thermoelectric device depend on the thermoelectric material. Bi-Te-based thermoelectric materials consist of p-type and n-type semiconductors are characterized by an excellent dimensionless figure of merit (ZT). In this study, we investigated the effect of the Bi/Sb compositional ratio on the thermoelectric properties in p-type Bi–Sb–Te alloys. Bi–Sb–Te powders were prepared by melting-grinding process. The sintered bodies were fabricated by the spark plasma sintering method, which allows short time sintering for controlling the growth of particles. By controlling the Bi/Sb ratio, the carrier concentration could be optimized. An increase in the Bi concentration led to a decrease in the carrier concentration and thermal conductivity, whereas the See-beck coefficient and specific resistance were increased due to phonon scattering. The thermoelectric ZT value was found to be dependent on changes in the thermal and electrical properties. The best carrier concentration value (2.46 x 1019/cm2) and the highest ZT value (1.3) were achieved for x = 0.4 in BixSb2−xTe3.