Effect of the Cu vacancy on the thermoelectric performance of p-type Cu1−xInTe2 compounds

In this study, the effect of Cu vacancy on the thermoelectric performance of Cu1-xInTe2 is reported, where x is 0, 0.04, 0.06, 0.08 and 0.10. Cu vacancy can yield excess holes lifting the carrier density of CuInTe2, which is an intrinsic p-type semiconductor. Meanwhile, the mass fluctuation caused by Cu vacancy attributes to the enhanced point defects phonon scattering, resulting in a reduced lattice thermal conductivity. The optimum Cu vacancy content is found to be 0.04, attaining a maximum zT value of 0.83 at 820 K. Meanwhile, there is a 50% enhancement compared to that of pure sample which arises from the large power factor and the relatively low thermal conductivity. Our result indicates the great potential of Cu1-xInTe2 for thermoelectric application at middle-temperature.