| Abstract
| - Layered structures of well-aligned carbon nanotubes were grown using three variations of vapor-phase chemicalvapor deposition growth processes. The reactants (typically ferrocene and benzene) were introduced eitherdirectly to a heated furnace or carried into the furnace by evaporation or spray pyrolysis in an argon flow.Thick mats of densely packed, well-aligned nanotubes were produced when the reactants were continuouslyintroduced to the reaction; however, when the reactant flow was interrupted, the pauses allowed growth tostop and then restart as a new layer. These pauses were achieved by either completely stopping the reactantflow for a given time or by modifying the dispensing system to introduce the reactants in discrete drops.Time intervals between drops were varied between 20 s and 120 s, with distinct layers observed for pausesof 30 s or greater. The best results were achieved when drops of a catalyst-rich solution were alternated withdrops of pure benzene. Layers were grown with thicknesses ranging from several microns to several hundredmicrons, and structures were grown with well over 100 layers.
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