9-13 July 2012
Electronic transport in a rope of metal filled single walled carbon nanotubes
Presented by Ms. Siphephile NCUBE on 12 Jul 2012 from 14:30 to 14:50
Type: Oral Presentation
Track: Track A - Division for Condensed Matter Physics and Materials
Filling of single walled nanotubes (SWNT) with chosen materials opens new possibilities of generating a nearly one dimensional structure by encapsulating a nanowire into a nanotube with a very small diameter. To date researchers have done considerable work on filling multi- and double walled nanotubes due to their larger diameters compared to SWNT's. SWNT's provide a platform to study the nanowire-nanotube interaction. High purity SWNT’s were synthesized by laser ablation and filled by a wet chemistry technique. Filling efficiency was investigated through electron microscopy.Raman spectroscopy studies showed a shift in the radial breathing mode frequencies indicating a decrease in diameter as the metal is encapsulated into the nanotube. We investigated the electronic and magnetic properties of individual and bundled nickel filled SWNT's using low temperature and magneto-resistance studies. The bundle of tubes exhibits semimetallic behavior with a T<sup>2</sup> temperature dependence. A very small energy gap has been observed in the I-V characteristics of these samples which show step like features related to resonant tunneling phenomena. On the other hand individual tubes showed a metallic nature from 300K down to 140K and a weakly activated conduction at low temperatures, below 140K complimented by the non exponential I-V characteristics. This study can be used to develop an understanding of the metal-nanotube interaction and the overall effect of the filler material on the electronic and magnetic properties of SWNT for nanoelectronic and spintronic applications.
Somnath Bhattacharyya, Somnath.Bhattacharyya@wits.ac.za, University of the Witwatersrand