Performance of Bi₂Te₃ Thermoelectric Element Improved by Means of Contact System Ni/Ta-W-N/Ni

In this paper the materials with improved thermoelectric properties developed based on Bi₂Te₃ were used for the production of thermoelectric generator. It allowed to extend the operating temperature range of the material to 550 K. Bi_2.0Te_2.4Se_0.6 doped with 0.12 wt% CuBr (dimensionless coefficient ZT = 1.1 at a temperature of 450–550 K) was used as a material for manufacturing n-type branches. Bi_0.4Sb_1.6Te_3.0 doped with 0.12 wt% PbCl₂ and 1.5 wt% Te (dimensionless coefficient ZT = 1.2 at a temperature of 450–550 K) was used as a material for manufacturing p-type branches. The following materials were used as the contact system: 100 nm layer of nickel as the ohmic contact layer; 100 nm layer of amorphous alloy Ta-W-N as a diffusion barrier layer; and 400 nm layer of nickel as a wetting layer for soldering. Study of adhesion of this contact system demonstrated good quality. The breakout force was 12 MPa.