Transport properties of nanocomposite thermoelectric materials based on Si and Ge

The modification of transport properties (thermal conductivity, electrical conductivity, and See-beck coefficient) of nanostructured thermoelectrics based on Ge and Si–Ge with inclusions of the second phase has been investigated experimentally. In the Ge-C$_{60}$ nanocomposite, modifying inclusions are the fullerene C$_{60}$ located along the germanium grain boundaries and 1- to 5-nm SiC nanocrystals in the Si–Ge–SiC nanocomposite. In particular, the presence of these inclusions in the nanocomposite leads to an increase of the Seebeck coefficient in the temperature range above 600 K and, in general, to an increase in the thermoelectric figure of merit ZT by a factor of 1.5–2 as compared to the corresponding characteristics of nanostructured thermoelectrics based on Si–Ge without modifying inclusions of the second phase.