A simple method of producing aligned carbon nanotubes from an unconventional precursor - Camphor

Vertically aligned multi-wall carbon nanotubes of diameter 20-40 nm and length similar to200 mum were grown on quartz substrate by pyrolyzing camphor with ferrocene catalyst at 900 degreesC in argon atmosphere at ambient pressure. Catalyst requirement with camphor was found to be low by a factor of 10 as compared to available reports of aligned nanotubes from conventional precursors. Because of the low catalyst requirement with camphor, as-grown nanotubes are least contaminated with metal particles, whereas the oxygen atom present in camphor helps in oxidizing amorphous carbon in-situ, eliminating the need of post-deposition purification. Good graphitization of the tube layers was observed by TEM, whereas high purity was confirmed by EDX analysis. The estimated yield of as-grown nanotubes is similar to90%. (C) 2003 Elsevier Science B.V. All rights reserved.