Transport properties of nanocomposite thermoelectric materials based on Si and Ge

Abstract

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-C60 nanocomposite, modifying inclusions are the fullerene C60 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.