Single-Crystal Microwires Based on Doped Bi for Anisotropic Thermoelectric Devices

Abstract

We have investigated the possibility to use a microwire of BiSn to design an anisotropic thermoelectric generator. The glass-coated microwire of pure and Sn-doped bismuth was obtained by the Ulitovsky method; it was a cylindrical single-crystal with orientation (1011) along the wire axis; the C3 axis was inclined at an angle of 70º to the microwire axis. It is found that doping of bismuth wires with tin increases the thermopower anisotropy in comparison with Bi by a factor of 2 – 3 in the temperature range of 200 – 300 K. For a Bi microwire with a core diameter of 10 μm with a glass coating with outer diameter of 35 μm, the transverse thermopower is ~ 150 μV/(K*cm); for BiSn, 300 μV/(K*cm). The design of an anisotropic thermogenerator based on BiSn microwire is proposed. The miniature thermogenerator will be efficient for power supply of devices with low useful current. In addition to the considerable thermopower anisotropy of BiSn wires in a glass coating, they exhibit stable thermoelectric properties, high mechanical strength and flexibility, which allows designing thermoelectric devices of various configurations on their basis.