Fabrication and Thermoelectric Properties of Bulk Si$_{0.8}$Ge$_{0.2}$-FeSi$_{2}$ Nanocomposite

We report enhancement of thermoelectric figure of merit (ZT) in bulk nanocomposites of n-type Si$_{0.8}$Ge$_{0.2}$-FeSi$_{2}$. The nanocomposite material was prepared via rapid sintering of the mixed powder of Si$_{0.8}$Ge$_{0.2}$ and FeSi$_{2}$ in a die under axial pressure. The thermoelectric properties of the samples were measured versus temperature. A remarkable reduction in thermal conductivity was observed while the thermoelectric power factor (Seebeck coefficient squared times the electrical conductivity) was maintained compared to the corresponding properties of the crystalline Si$_{0.8}$Ge$_{0.2}$. As a result the ZT increased to about 1.2 at 950 C, which is 20{\%} more than that of the n-type crystalline silicon germanium.