Enhanced thermoelectric performance of a highly ordered vertical Bi_0.5Sb_1.5Te₃ pillar array device with optimized interconnect

An approach for fabrication of micro-devices integrating highly ordered vertical Bi_0.5Sb_1.5Te₃ pillar array was reported. The pillar array was successfully achieved by a simple magnetron co-sputtering method. This pillar array structure was clear with each pillar diameter <100 nm. The measurement result showed that the Bi_0.5Sb_1.5Te₃ pillar array was beneficial for improvement of in-plane thermoelectric properties, being a promising choice for planar micro-devices. The power generation and cooling performance of the Bi_0.5Sb_1.5Te₃ pillar array micro-device with optimized interconnect were tested and found to be very superior to those of the bulk material and the ordinary film devices. For a typical parallel device with 38 Bi_0.5Sb_1.5Te₃ pillar array elements, the output voltage and estimated maximum power were up to 10.2 mV and 9.63 μW, respectively, for a temperature difference of 70 K. The device could produce a 10.5 K maximum temperature difference at current of 70 mA. Introduction of such uniquely ordered pillar array structure and optimized interconnect into planar micro-devices is therefore a very promising approach.