Enhancement of Doping Concentration in P-Type SiGe Thermoelectric Alloy with the Addition of CrSi2

We report enhancement in doping concentration of p- type SiGe by small addition of CrSi₂ into the matrix. P-type SiGe thermoelectric alloy was synthesized by melting the elemental powders with and without addition of CrSi₂. The transport properties of both ingots were measured in temperature range of 25- 850 ̊C. The results showed that the addition of CrSi₂ to SiGe enhances its electrical conductivity which is explained by enhancement in carrier concentration. Power factor of the composite sample was improved. Consequently, its figure-of-merit, ZT, increased compared with that of SiGe. In this study, the effect of nanostructuring on the SiGe : CrSi₂ composite was further studied and its transport property were compared with those of crystalline composite sample. The DTA thermograph of SiGe : CrSi₂ suggested the possibility of reaction between Cr and Si during sample synthesis which may resulted in formation of small amount of Cr_1-xGe_x (x=0.02- 0.03) alloy in the matrix.