Enhancing the thermoelectric performance of Sn 0.5 Ge 0.5 Te via doping with Sb/Bi and alloying with Cu 2 Te: Optimization of transport properties and thermal conductivities

The current work provides a comparative study of the thermoelectric properties of the Sn_0.5Ge_0.5Te phases doped with Sb and Bi and alloyed with Cu₂Te. The Sn_0.5Ge_0.5Te composition was chosen based on the fact that it delivers the highest ZT value within the Sn_1-xGe_xTe series (x≤ 0.5). Doping Sn_0.5Ge_0.5Te with electron-richer Sb and Bi improves both the charge transport properties and thermal conductivities. Alloying with Cu₂Te optimizes the thermoelectric performance of the samples even further, yielding a ZT value of 0.99 for (Sn_0.5Ge_0.5)_0.91Bi_0.06Te(Cu₂Te)_0.05 at 500 °C. Hall measurements were performed to understand the effects of doping and alloying.