Fabrication and evaluation of microscale thermoelectric modules of Bi₂Te₃-based alloys

Microscale thermoelectric modules are fabricated by a facile process based on mechanical cutting combined with photolithography processes. Fine-grained materials of p-type Bi_0.5Sb_1.5Te₃ and n-type Bi₂Te₃ dispersed with 0.5 vol% nano-SiC particles, which show improved mechanical strength than that without SiC additions, were prepared by spark plasma sintering (SPS) for the module microfabrication. The fabricated modules have 28 pairs of thermoelectric legs, each of them being as fine as 200 × 400 μm² in cross-section with a height up to 600 μm, which were connected in series by Ni-Cu electrodes made by photolithographic patterning and magnetron sputtering. Such a microscale module was evaluated under both Seebeck and Peltier working modes. According to the Seebeck mode, when the module is heated under a lamp, the maximum open output voltage and the maximum output power are about 20 mV and 0.15 μW (1.6 μW cm^-2), respectively. In the Peltier mode, a temperature difference of approximately 7 K is obtained with the input current of 4 mA. © 2010 IOP Publishing Ltd.