Table of Contents
Journal of Nanoscience
Volume 2014, Article ID 404519, 7 pages
http://dx.doi.org/10.1155/2014/404519
Research Article

Modulation of Carbon Nanotube Metal Contacts in Gaseous Hydrogen Environment

1Electrical and Computer Engineering, University of British Columbia, 341-2355 East Mall, Vancouver, BC, Canada V6T 1Z4
2School of Electronics and Computer Science, University of Southampton, Highfield, Southampton SO17 1BJ, UK

Received 31 December 2013; Accepted 1 March 2014; Published 27 March 2014

Academic Editor: Oleg I. Lupan

Copyright © 2014 A. R. Usgaocar et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

Abstract

Carbon nanotubes (CNTs), contacted by electrodeposited Pd0.59Ni0.41 alloys, are characterised using electrical measurements and Raman spectroscopy. The high workfunctions of Nickel and Palladium form an ohmic contact with the CNT valence band, but the contact properties change on Hydrogen exposure due to a reduction in the PdNi workfunction and the realignment of the PdNi Fermi level with the CNT band structure. A PdNi contacted semiconducting CNT exhibited significantly lower currents after Hydrogen exposure while a metallic CNT exhibited a small current increase. The semiconducting and metallic natures of the CNTs are confirmed by their Raman spectra. This study demonstrates a technique for modulating the PdNi-CNT contact and differentiating between semiconducting and metallic CNTs via contact modulation. It also provides experimental evidence of the theoretical allocation of features in the CNT Raman spectra.