Thermoelectric Properties of Single Crystals of a Pb-Enriched Pb0.75Sn0.25Te Solid Solution

Single crystals of Pb_0.75Sn_0.25Te solid solutions containing up to 1.0 at % excess Pb have been grown by the Bridgman method, and their thermoelectric properties have been studied in the range ~90–300 K before and after heat treatment at 673 and 773 K. The results demonstrate that excess Pb and heat treatment conditions have a significant effect on the electrical conductivity, thermoelectric power, and thermal conductivity of the material and their temperature variation. The highest 300-K thermoelectric figure of merit is offered by the material containing 1.0 at % excess Pb and annealed at 773 K, which is due to its rather high thermoelectric power (~160.1 μV/K) and low lattice thermal conductivity (∼1.04 × 10^–2 W/(cm K)).