Thermoelectric properties of carbon nanotubes layers

Abstract

Thermoelectric power (TEP) of the carbon nanotubes (CNTs) films, grown by radiofrequency plasma-enhanced chemical vapor technology onto silicon substrates, has been measured. Two different metal contacts of Cr-Al and Cr-Au have been fabricated for the CNTs-based thermocouples and preliminarily investigated. The CNTs-based thermocouples exhibit large values of TEP due to the Schottky barriers at semiconducting CNTs-metal junctions. The highest TEP of 40.7 μV/K has been achieved for the thermocouple CNTs/Cr-Al. This value is enhanced of about 2 times compared to single-walled CNTs bundles reported in literature (Collins et al. Science 287:1801-1804, 2000), and comparable to isolated suspended single-walled carbon nanotubes with Pt-electrodes reported in literature (Yu et al. Nano Lett 5(9):1842-1846, 2005) as well. The CNTs-thermocouples exhibit linear relationship for the output voltage versus temperature in the range from 20 to 70°C by providing an interesting nanomaterial for energy applications and temperature and/or radiation microsensors. © 2011 Springer Science+Business Media B.V.