Thermoelectric properties of n-type (Bi 2Se 3) x(Bi 2Te 3) 1− x prepared by bulk mechanical alloying and hot pressing

Abstract

Starting from element Bi, Se and Te granules, n-type (Bi 2Se 3) x (Bi 2Te 3) 1− x with different chemical composition ( x=0.025, 0.05, 0.075, 0.10 and 0.15) were prepared via bulk mechanical alloying (BMA) and hot pressing (HP). Effects of chemical composition, doping content and annealing on thermoelectric properties were reported. The range x≤0.050 is more favorable than other chemical compositions for the thermoelectric properties of BMAed (Bi 2Se 3) x (Bi 2Te 3) 1− x . When doping with SbI 3, both the electrical resistivity and the Seebeck coefficient of (Bi 2Se 3) 0.05(Bi 2Te 3) 0.95 decrease, thus resulting in no improvement of the figure of merit. On the other hand, annealing the as-HPed (Bi 2Se 3) 0.05(Bi 2Te 3) 0.95 a sufficiently long time is helpful to improve thermoelectric properties, and the maximum figure of merit of (Bi 2Se 3) 0.05(Bi 2Te 3) 0.95 is 2.31×10 −3/K.