Thermoelectricity for crystallographic anisotropy controlled Bi–Te based alloys and p–n modules

Abstract

The p-type (Bi 2Te 3) 0.2(Sb 2Te 3) 0.8 and n-type (Bi 2Se 3) 0.05(Bi 2Te 3) 0.95 alloys were fabricated by the shear extrusion to enhance texture evolution. Transverse Direction (TD) inverse pole figure analysis via electron backscattered diffraction patterns (EBSP) showed that most of the crystallographic orientations of shear-extruded sample were well aligned in the range deviating from 60° to 90° from the c-axis. The electric resistivity of p-type controlled to be 1.008 × 10 −5 Ω m, which is nearly equal to that of unidirectionally grown sample. The maximum figure of merit for p-type alloy was found to be z = 3.03 × 10 −3 K −1 and for the n-type, z = 2.26 × 10 −3 K −1. Thermoelectric p–n modules were prepared via the spark plasma sintering (SPS) solid bonding for evaluation on their thermoelectricity. The power generation characteristic of p–n modules was also evaluated for various temperature differences between cold and hot sources.