2002 Volume 43 Issue 4 Pages 681-687
Mechanical alloying followed by pulse discharge sintering (MA-PDS) has been employed to develop the bulk (Bi1−xSbx)2Te3 thermoelectric materials with various Sb alloying contents. Substitutional solid solutions of (Bi1−xSbx)2Te3 are formed in the whole Sb content range by MA-PDS process. The sintered compacts are dense and have refined microstructures. Systematic investigations on the electrical, thermal and thermoelectric properties reveal that the transport properties of the obtained (Bi1−xSbx)2Te3 samples are quite sensitive to the Sb alloying content. At room temperature, the samples with x<0.57 exhibit n-type semi-conduction. However, at x>0.57, the samples become p-type. The pure constituents of Bi2Te3 and Sb2Te3 as well as the Sb-poor, n-type samples exhibit the room-temperature figure of merit of the order of 1.0×10−3 K−1. High values of figure of merit have been obtained in the Sb-rich, p-type samples. The maximum value of 3.35×10−3 K−1 is attained at x=0.80, which corresponds to the carrier concentration and Hall mobility of 1.95×1019 cm−3 and 207 cm2/Vs, respectively.