Synthesis of Vertically Aligned Single- and Double-Walled Carbon Nanotubes without Etching Agents

Abstract

The number of graphene shells on carbon nanotubes (CNTs) can be rationally controlled to yield high-density, vertically aligned single- and double-walled CNTs. This was obtained by thermal chemical vapor deposition at 700 °C without the use of etching agents such as water, oxygen, or plasma. The key factors for this success are controlled dissociative adsorption of acetylene (C2H2) molecules and subnanometer thickness control of the Al/Fe/Mo trilayer films. We propose that an Al concave meniscus confines the actual growth surface areas of Fe/Mo catalytic nanoparticles and enables the control of the number of graphene shells on CNTs.

Low Temperature Synthesis of Carbon Nanotube on Si substrate Using Alcohol Gas Source in High Vacuum

“…The results were summarized in Fig. Since RBM peaks for large diameter CNTs are beyond the detection range of Raman spectroscopy [12], we plan to use transmission electron microscopy to estimate the correct diameter distribution of our CNTs in the future. The CNT diameters were estimated from the RBM peaks in the Raman spectra measured by excitation wavelengths of 514.5, based on the equation, d (nm) = 248/w (cm -1 ).…”

Growth Mechanisms of Vertically-aligned Carbon, Boron Nitride, and Zinc Oxide Nanotubes

“…By doing so, dense bundles of CNTs can be grown as shown in Fig. 2(c) either in single-, double-, or multi-walled structures [11].…”

“…Unlike CNTs and BNNTs, atoms at the surface of artificial nanotubes are not saturated with chemical bonds and thus readily functionalization with other molecules and atoms for achieving property modification. Because of the page limit, this article provides a brief summary on the possible growth mechanisms of vertically-aligned CNTs, [11][12][13] BNNTs, [14,7] and ZnO NTs. [6][7][8] Readers are encouraged to refer to the related references for SiNTs and more comprehensive description on CNTs, BNNTs, and ZnO NTs.…”

Synthesis and characterization of low dimensional carbon materials

“…In this method, the hydrocarbon compound vapor decomposes at relative lower temperatures (~700-1000 o C) and forms SWNTs in the presence of the metal catalyst with very small sizes (1~2 nm) [17,18]. Generally, the metal catalysts are cobalt (Co), nickel (Ni) [32].…”

“…SEM/HRTEM images and Raman spectrum of the VA-SWNT film (laser excitation wavelength is 633 nm). Adapted from kayastha et al[32].…”