Nanostructuring and thermoelectric properties of semiconductor tellurides

Bulk nanostructured (Bi,Sb)
₂
Te
₃
compounds and GeTe based amorphous/nanocrystal composites have been successfully fabricated by the combined hydrothermal/hot-pressing and quenching/annealing methods, respectively. The (Bi,Sb)
₂
Te
₃
nanopowders synthesized by hydrothermal method exhibit a hollow-like structure. After hot-pressing, the nanoscale grains varying from tens to hundreds of nanometers were found in the bulk sample. The maximum ZT value of this (Bi,Sb)
₂
Te
₃
sample is higher than the zone-melt one at room temperature. The sizes of the nanocrystals in the bulk GeTe nanocomposites were below 10 nm, the presence of which contributed to the remarkable improvement of the electrical conductivity and thermoelectric power factor compared to the amorphous precursors.