Large enhancement of thermoelectric performance of InTe compound by sintering and CuInTe₂ doping

InTe is a newly emerging thermoelectric material working at a middle temperature range with an ultralow thermal conductivity. Nevertheless, the figure of merit (ZT) of InTe currently is way too inappreciable compared with other material systems. In this work, we present that a peak ZT as high as ∼0.8 is achieved at 723 K in InTe composited with 1.02% of CuInTe₂ prepared by spark plasma sintering. The large improvement of thermoelectric performance in sintered InTe mainly comes from the enhancement of conductivity. The reasons for this phenomenon are investigated as well. We find that extra In vacancies which lead to an increment of hole concentration and the energy barrier at grain boundaries are responsible for the behavior of electrical properties. Besides, a small amount of CuInTe₂ also contributes to the improvement of power factor, which leads to higher ZT.