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 Sn0.5Ge0.5Te phases doped with Sb and Bi and alloyed with Cu2Te. The Sn0.5Ge0.5Te composition was chosen based on the fact that it delivers the highest ZT value within the Sn1-xGex Te series (x <= 0.5). Doping Sn0.5Ge0.5Te 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 (Sn0.5Ge0.5)(0.91)Bi0.06Te(Cu2Te)(0.05) at 500 degrees C. Hall measurements were performed to understand the effects of doping and alloying.