The anisotropic powder metallurgy of n-type Bi2Te2.85Se0.15 thermoelectric material

Abstract

The anisotropic powder metallurgy of n-type Bi2Te2.85Se0.15 doped with bromines was studied by both x-ray diffraction and thermoelectric measurements. The statistical orientation of platelet-like grains in the samples was characterized using the orientation factor estimated by the Lotgering formula from (0,0,1) x-ray diffraction intensities. It is demonstrated that the orientation factor which is strongly influenced by the hot-pressing conditions and the particle size of the starting material has a strong effect on the thermoelectric properties of the samples in this system. This implies that the powder metallurgy has the additional freedom of controlling the thermoelectric properties in addition to the doping level in the grains.