Thermoelectric properties of Sn-doped Bi-Sb

The Seebeck coefficients, electrical resistivities, and total thermal conductivities are reported for temperatures between 10 and 300 K for p-type Bi-Sb alloys made by Sn-doping at the 5% level or below. Alloys are investigated for Sb contents at both extremes of the semiconducting region of the Bi-Sb alloy solid solution, 7-10% Sb and 18-20% Sb. The behavior of all the alloys is relatively similar, and the best p-type material found, Bi_0.885Sb_0.075Sn_0.04, has a maximum thermoelectric figure of merit of ZT = 0.08 at 200 K. The thermoelectric efficiency of the optimal n-p couple in this alloy system peaks at ZT = 0.13 at a temperature of 200 K.