p-type SiGe-based composite produced by mechanical alloying and spark plasma sintering

We report on a study of bulk SiGe-MnTe composites obtained via spark plasma sintering of mixed powders composed of SiGe that was fabricated by mechanical alloying and MnTe prepared via solid-state reaction. The presence of MnTe in the SiGe matrix led to an increase in the electrical conductivity by ∼ 50 % and a decrease in the lattice thermal conductivity of the samples by ∼ 28 %, while the Seebeck coefficient was reduced from 252 μV K−1 to 197 μV K−1 at 1000 K. As a result, the peak zT of 0.75 was obtained for pristine Si80Ge20B2, and 0.8 for Si80Ge20B2 + 4 wt% MnTe at 1000 K.