Improved thermoelectric performance of a film device induced by densely columnar Cu electrode

In this study, it was found that the columnar Cu film is similar as a parallel microchannel which can create some sort of channels for the easy transport of electrons and phonons in the device. The p-Bi_0.5Sb_1.5Te₃, n-Bi₂Se_0.3Te_2.7 and Cu films were fabricated by a magnetron sputtering method. These films have been integrated into low-dimension cross-plane devices using mask-assisted deposition technology. The performance of the micro-device with densely columnar Cu film electrode has been tested, which was very superior to that of the device with ordinary structure electrode. For the typical device with 98 pairs of p/n couples, the output voltage and maximum power were up to 120.5mV and 145.2μW, respectively, for a temperature difference of 4K. The device could produce a 14.6K maximum temperature difference at current of 160mA. The response time to reach the steady condition was less than 2S. The results prove that excellent performance of micro-device can be realized by integrating the densely columnar Cu electrode.