Thermoelectric properties of p-type (Bi,Sb)(2)Te-3 alloys fabricated by the hot pressing method

Abstract

P-type (Bi0.25Sb0.75)(2)Te-3 powders were fabricated by melting/grinding and mechanical alloying processes. Thermoelectric properties of the hot-pressed (Bi0.25Sb0.75)(2)Te-3 were characterized-with the powder processing method, powder size, hot pressing temperature, and the amount of excess-Te dopant. Specimens fabricated by melting/grinding exhibited lower Seebeck coefficient, lower electrical resistivity and higher thermal conductivity, compared to the specimens prepared by mechanical alloying. 3 wt.% excess Te-doped (Bi0.25Sb0.75)(2)Te-3, fabricated by melting/grinding and hot pressing at 550 degrees C, exhibited a figure-merit of 3.2 x 10(-3)/K. For 1 wt.% excess Te-doped specimen prepared by mechanical alloying and hot pressing at 550 degrees C, a figure-merit of 3.05 x 10(-3)/K was obtained.