The texture related anisotropy of thermoelectric properties in bismuth telluride based polycrystalline alloys

Large size bismuth telluride based polycrystalline alloys have been prepared to investigate the texture-related anisotropy of thermoelectric properties. X-ray diffraction analysis indicated that the n-type alloy was more easily (001) oriented than the p-type one. Both the electrical and thermal conductivities showed strong anisotropy in the textured samples, while the Seebeck coefficient and the ZT were almost isotropic. However, as the electrical and thermal conductivities were measured along different directions, the ZT could be overestimated up to ∼60%. A relationship between the texture degree and the anisotropy of the thermal conductivity has been proposed.