Realizing high thermoelectric performance for p-type SiGe in medium temperature region via TaC compositing

Abstract

SiGe is recognised as an excellent thermoelectric material with superior mechanical properties and thermal stability in regions with high temperatures. This study explores a novel strategy for co-regulating thermoelectric transport parameters to achieve high thermoelectric properties of p-type SiGe in the mid-temperature region by incorporating nano-TaC into SiGe combined ball milling with spark plasma sintering. By optimizing the amount of TaC in the SiGe matrix, the power factors were significantly increased due to the modulation doping effect based on the work function matching of SiGe with TaC. Simultaneously, the ensemble effect of the nanostructure leads to a significant decrease in thermal conductivity. Thus, a high ZT of 1.06 was accomplished at 873 K, which is 64 % higher than that of typical radioisotope thermoelectric generator. Our research offers a novel strategy for expanding and enhancing the thermoelectric properties of SiGe materials in the medium temperature range.