Comparison of the thermoelectric properties of (Bi,Sb)(2)Te(3) alloys prepared by powder metallurgy with single crystals

Abstract

Thermoelectric properties of the polycrystalline (Bi(1-x)Sb(x))(2)Te(3) (0 less than or equal to x less than or equal to 1) alloys, prepared by various powder metallurgy such as mechanical alloying and melting/grinding, were measured and compared with the characteristics of single crystals. Contrary to the p-type behavior of the single crystals in all compositions of 0 less than or equal to x less than or equal to 1, a p-n transition occurred at about 0.67 mol% Sb(2)Te(3) for the alloys prepared by powder metallurgy. Among the p-type (Bi(1-x)Sb(x))(2)Te(3) (x greater than or equal to 0.7) processed by powder metallurgy, (Bi(0.2)Sb(0.8))(2)Te(3) exhibited,the highest figure-of-merit of 3.05x10(-3)/K. Thermoelectric properties of the hot-pressed (Bi(0.2)Sb(0.8))(2)Te(3) with addition of BN powders as scattering centers were also investigated.