Improved thermoelectric performance of nanostructured tellurium thin films

Abstract

AbstractWe report nanostructured Te thin film exhibiting a high figure-of-merit (ZT) of ~ 0.34 at 493 K. The films exhibit temperature enhanced electrical conductivity ~ 43 Scm−1, very high Seebeck coefficient of ~ 385 µV−1K−1 contributed by non-degenerate valence bands and low thermal conductivity ~ 0.9−1 Wm−1K−1 through suppression of bipolar effect. The ZT of nanostructured films is ~ 142% higher than the annealed films having larger grain size. The high Seebeck coefficient (~ 405 µV−1K−1) of nanostructured Te films near room temperature prompted us to make a device, which was subjected to a very small temperature difference of ~ 4 K by touching with finger and produced an open circuit voltage of ~ 18 mV. The periodic generation of this open circuit voltage with fast response when repeatedly touched with finger, suggest the utility of these films in real time human touch applications and temperature sensing.