In-situ Doping of Thermoelectric Materials Based on SiGe Solid Solutions during Their Synthesis by the Spark Plasma Sintering Technique

Abstract

The results of investigation of thermoelectric materials fabricated by spark plasma sintering and based on Si_{1 –x}Ge_x solid solutions doped with Sb to a concentration of 0–5 at % are presented. It was found that, at Sb concentration below 1 at %, efficient doping of the solid solution was carried out during the sintering process, which allowed us to form a thermoelectric material with a relatively high thermoelectric figure of merit. An increase in the concentration of antimony in the range of 1–5 at % led to a change in the mechanism of doping, which resulted in an increase in the resistance of materials and the segregation of Sb into large clusters. For such materials, a significant decrease in the Seebeck coefficient and thermoelectric figure of merit was noted. The highest obtained thermoelectric figure of merit (ZT) with Sb doping was 0.32 at 350°C, which is comparable with known analogues for the Ge_xSi_{1 –x} solid solution.