Thermoelectric properties of the hot-pressed (Bi0.2Sb0.8)(2)Te-3 alloy with addition of BN and WO3 powders

Thermoelectric properties of the (Bi0.2Sb0.8)(2)Te-3 alloy, fabricated by m echanical alloying and hot-pressing, were investigated with addition of BN and WO3 powders as phonon scattering centers. The Seebeck coefficient and t he electrical resistivity of the hot-pressed (Bi0.2Sb0.8)(2)Te-3 alloy incr eased with increasing the volume fraction of BN and WO3. Although the therm al conductivity of the hot-pressed (Bi0.2Sb0.8)(2)Te-3 alloy decreased with increasing the volume fraction of BN and WO3 due to the reduction of kappa (e)l, the lattice thermal conductivity was not lowered. The figure-of-merit of the hot-pressed (Bi0.2Sb0.8)(2)Te-3 alloy, 3.05 x 10(-3)/K without addi tion of BN and WO3, decreased with increasing the volume fraction of BN and WO3, because the increment of the electrical resistivity was much larger t han the decrement of the thermal conductivity due to the grain refinement. (C) 2000 Kluwer Academic Publishers.