Relationship between thermoelectric properties and microstructure on n-type (Bi2Te3)0.95(Bi2Se3)0.05 ceramics prepared from mixed powders

Abstract

The n-type (Bi2Te3)0.95(Bi2Se3)0.05 was synthesized by modified pulverized and intermixed sintering elements (PIES) method and its figure of merit was evaluated to be 1.8 × 10-3/K (25°C). The milling mechanism obeyed to the Kick's law and Tanaka's equation. No anisotropy of electrical transport phenomena in thermoelectric properties was observed, because the microstructure consisted of non-oriented grains due to use the milling powders of Bi, Te, and Se as starting materials. Thermal conductivity was smaller than that of single crystal by the large phonon scattering due to small grain, and Seebeck coefficient and resistivity were smaller than that of single crystal due to incompletely formate solid solution and oxides of sintered body.