Fabrication of Π-structured Bi-Te thermoelectric micro-device by electrodeposition

A Π-structured Bi-Te micro-thermoelectric device with a large upper electrode, i.e., an umbrella-type device, was fabricated via electrodeposition, and the effect of the size of the electrode was evaluated. The Bi-Te thermoelectric materials were electrodeposited from HNO₃-based aqueous electrolyte. The device consisted of eight arrays, each consisting of 110 thermoelectric units, each of which was electrodeposited onto the patterned substrate with an array of 50 × 50 μm² holes that were 20 μm deep. The deposition conditions for the n-type and p-type Bi-Te films were optimized to enable patterned electrodeposition of the materials to yield dense and uniform deposits. Accordingly, the materials were selectively deposited in a pattern to fabricate the thermoelectric micro-device. The resultant umbrella-type device, whose electrode is 1.65 times larger than smaller electrode, generated 4.57 times more power than the device with a smaller electrode. Therefore, we confirmed the improvement power by using an umbrella-type device.