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 Bi0.5Sb1.5Te3 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.