Bi₂Te₃-Related Thermoelectric Samples with Aligned-Texture Prepared by Plastic Deformation

Abstract

Plastic deformation study of Bi₂Te₃-related materials was performed. The ingots were grown by the Bridgman method using source materials with nominal compositions of Bi_0.5Sb_1.5Te₃, Bi₂Sb_2.85Se_0.15 and Bi_1.8Sb_0.2Te_2.85Se_0.15. Disks were cut from the ingots, and were then deformed by either cold-pressing or 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 the Bi₂Te₃ structure, and the diffraction patterns indicate that the surfaces and bottoms of the samples were highly oriented in the hexagonal (00-l) plane. Hall effect measurements show the carrier concentration of the samples to be at an order of magnitude of 10²⁵ m⁻³ at room temperature. The power factor for the samples after hot-press deformation exceeded that for the original ingots. The results suggest that hot-press deformation enhances the thermoelectric properties of Bi₂Te₃-related materials.