Microstructure and thermoelectric properties of n-type 95%Bi2Te3-5%Bi2Se3 alloy produced by rapid solidification and hot extrusion

n-type SbI3-doped 95%Bi2Te3 + 5%Bi2Se3 compounds were prepared by a rapid solidification and extrusion at the temperature range 420-480 degreesC using an extrusion ratio of 25:1. The microstructure and thermoelectric properties of the compounds were investigated as a function of extrusion temperature. The fabricated powder consists of homogeneous Bi2Te3 + Bi2Se3 solid solution and the relative density of over 99% was obtained by hot extrusion. The values of Seebeck coefficient for the compounds hot extruded at 420, 450, and 480 degreesC were -160.8, -170.2, and -165.7 muV K-1, respectively. The values of electrical resistivity (rho) for the compounds hot extruded at 420, 450, and 480 degreesC were 0.49, 0.57, and 0.51 x 10(-5) Omega m, respectively. The maximum power factor value of the compounds hot extruded at 480 degreesC was 53.8 x 10(6) muW cm(-1) K-2. (C) 2003 Elsevier Science Ltd. All rights reserved.