title: Dual catalytic purpose of the tungsten filament during the synthesis of single-helix carbon microcoils by hot-wire CVD.
abstract: We report on the deposition of crystalline single-helix carbon microcoils, in the as-deposited state, by the hot-wire chemical vapor deposition process without any special preparation of nano-sized transition metal catalysts and subsequent post-deposition annealing. Tungsten, originating from the heated tungsten filament, is identified as the catalyst material responsible for the growth of the microcoils. High-resolution transmission spectroscopy, combined with Raman spectroscopy, confirm that the as-deposited microcoils are crystalline, which is induced by the high deposition temperature in the vicinity of the heated filament. These results suggest a simplified, less tedious deposition process for the growth of carbon microcoils, once the process has been optimized.
authors.affiliation: National Centre for Nano-Structured Materials, CSIR Materials Science and Manufacturing, PO Box 395, Pretoria 0001, South Africa.
authors.forename: C J
authors.initials: CJ
authors.lastname: Oliphant
authors.forename: C J
authors.initials: CJ
authors.lastname: Arendse
authors.forename: G F
authors.initials: GF
authors.lastname: Malgas
authors.forename: D E
authors.initials: DE
authors.lastname: Motaung
authors.forename: T F G
authors.initials: TF
authors.lastname: Muller
authors.forename: D
authors.initials: D
authors.lastname: Knoesen