Abstract
We discuss the synthesis of carbon nanotubes (CNTs) and graphene by catalytic chemical vapour deposition (CCVD) and plasma-enhanced CVD (PECVD), summarising the state-of-the-art understanding of mechanisms controlling their growth rate, chiral angle, number of layers (walls), diameter, length and quality (defects), before presenting a new model for 2D nucleation of a graphene sheet from amorphous carbon on a nickel surface. Although many groups have modelled this process using a variety of techniques, we ask whether there are any complementary ideas emerging from the different proposed growth mechanisms, and whether different modelling techniques can give the same answers for a given mechanism. Subsequently, by comparing the results of tight-binding, semi-empirical molecular orbital theory and reactive bond order force field calculations, we demonstrate that graphene on crystalline Ni(111) is thermodynamically stable with respect to the corresponding amorphous metal and carbon structures. Finally, we show in principle how a complementary heterogeneous nucleation step may play a key role in the transformation from amorphous carbon to graphene on the metal surface. We conclude that achieving the conditions under which this complementary crystallisation process can occur may be a promising method to gain better control over the growth processes of both graphene from flat metal surfaces and CNTs from catalyst nanoparticles.
Highlights
The rst single-wall carbon nanotubes (SWCNTs) were synthesised by high temperature techniques, all of which involve a metal catalyst
SWCNTs and multi-wall carbon nanotubes (MWCNTs) are commonly produced by catalytic chemical vapour deposition (CCVD) at much lower temperatures, ranging from 600–1300 K, or by plasma-enhanced CVD (PECVD), in which the gas is not activated by high temperatures as in thermal CCVD, but rather by applying a sufficiently strong voltage, causing gas breakdown
In (c), the work of nucleation, W, given by eqn (1.3), is shown as a function of nucleus size, a, with enthalpy of stabilization per unit area, DHA, taken from Fig. 7 and amorphous carbon (aC)–graphene energy per unit length, G, calculated from energy difference of defective graphene sheet relative to perfect graphene divided by perimeter
Summary
James Elliott is a Reader in Macromolecular Materials in the University of Cambridge, where he carries out research on multiscale computational modelling of so matter systems, including coarsegrained and molecular modelling of polymers, carbon nanotubes and their composites. He was a Visiting Fellow at Fitzwilliam College, Cambridge, UK in 2005 and 2006 His recent research focuses on understanding the nature of phase transitions during the synthesis of materials by numerical modelling. His chosen systems of interest range from base materials such as iron and steel to advanced materials such as carbon nanotubes and graphene. http:// www.mse.t.u-tokyo.ac.jp/shibuta/
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
