Effects of a reduction treatment and Te doping on thermoelectric properties of (Bi1-xSbx)2Te3 fabricated by mechanical alloying

(Bi1-xSbx)(2)Te-3 (0.75 less than or equal to x less than or equal to 0.85) thermoelectric materials were fabricated by mechanical alloying and hot pressing at 550 degrees C for 30 minutes with and without a reduction treatment of the mechanically alloyed powders. When the mechanically alloyed (Bi1-xSbx)(2)Te-3 powders were hot-pressed without a reduction treatment, a maximum figure-of-merit of 2.92x10(-3)/K at 300K was obtained for x = 0.8 composition. Although the electrical resistivity of the mechanically alloyed (Bi1-xSbx)(2)Te-3 decreased with a reduction treatment of the powders, the figure-of-merit was lowered due to the substantial decrease of the Seebeck coefficient. With addition of 1 wt% excess Te, the figure-of-merit of the reduction-treated (Bi0.2Sb0.8)(2)Te-3 could hp improved to be 3.33 X 10(-3)/K.