Thermoelectric properties of Bi/sub 2/Te/sub 3/-related materials prepared by pulse-current hot-pressing

Abstract

Hot-press deformation was performed for Bi/sub 2/Te/sub 3/-related samples. The ingots as the source material were grown by the Bridgman method with the nominal compositions of Bi/sub 0.5/Sb/sub 1.5/Te/sub 3/ and Bi/sub 2/Te/sub 2.85/Se/sub 0.15/ A disk cut from the ingot was deformed by hot-pressing under pulse-current heating. The crystal structures of the deformed samples were identified by X-ray diffraction. All diffraction peaks were assigned to Bi/sub 2/Te/sub 3/-type structure and the patterns indicate the samples were oriented in the hexagonal (00/spl middot/l) plane. The Hall effect measurements indicate that the carrier concentration of the samples is in the order of magnitude of 10/sup 25/ m/sup -3/ in the temperature range of 80 to 300 K. The power factor after the deformation exceeds those for the source ingots. The results indicate that the hot-press deformation can be expected to enhance thermoelectric properties of Bi/sub 2/Te/sub 3/-related materials.