Thermoelectric properties of the n-type 85%Bi(2)Te(3)-15%Bi(2)Se(3) alloys doped with SbI(3) and CuBr

Abstract

The temperature dependence of the Hail mobility Seebeck coefficient, electrical resistivity, thermal conductivity, and figure-of-merit of the Sbl(3) and CuBr-doped 85% Bi(2)Te(3)-15% Bi(2)Se(3) single crystals have been characterized at temperatures ranging from 77 K to 600 K. The scattering parameter in 85% Bi(2)Te(3)-15% Bi(2)Se(3) single crystal was determined as 0.1 from the temperature dependence of the carrier mobility. With increasing the amount of Sbl(3) or CuBr doping, the Seebeck coefficient of 85% Bi(2)Te(3)-15% Bi(2)Se(3) decreased and the temperature at which the Seebeck coefficient shows a maximum shifted to higher temperature. Compared to the Sbl(3)-doped specimens, the CuBr-doped single crystals exhibited higher (m*/m(0))(3/2)mu(c), implying that CuBr is a more effective dopant to im prove the material factor and thus the figure-of-merit of 85% Bi(2)Te(3)-15% Bi(2)Se(3). The maximum figure-of-merit of 2.0 x 10(-3)/K and 2.2 x 10(-3)/K was obtained for 0.1 wt % Sbl(3)-doped specimen and 0.03 wt % CuBr-doped specimen, respectively. (C) 1998 Kluwer Academic Publishers.