Enhancement of the thermoelectric performance of InTe via introducing Cd dopant and regulating the annealing time

Due to the lone-pair-induced anharmonic rattling, InTe exhibits intrinsically ultralow thermal conductivity , which was considered as a candidate for thermoelectric application. However, the poor electrical transport properties result in low thermoelectric conversion efficiency. In this work, Cd doping in InTe have been performed with the aim to optimize the carrier concentration and increase the power factor. Furthermore, an essential enhancement of carrier mobility can be realized via prolonging the annealing time, leading to improved thermoelectric performance. As a result, the maximum thermoelectric figure of merit zT of 0.87 at 773 K has been achieved for In 0.98 Cd 0.02 Te undergoing 7 days annealing treatment (In 0.98 Cd 0.02 Te-7days), which is 67% higher than the value of InTe after 2 days annealing (InTe-2days, zT  = 0.52@773 K). The average zT increases significantly from 0.26 for InTe-2days to 0.53 for In 0.98 Cd 0.02 Te-7days in the temperature range of 323–823 K. Thus, both introducing Cd dopant and regulating the annealing time have obvious effects on improving the thermoelectric performance of InTe.