A Tight-Binding Molecular Dynamics Simulation Analysis of Carbon Nanotube Growth Process Parameters

This paper employs tight-binding molecular dynamics simulations to investigate the effects upon the final nanotube morphology of three principal carbon nanotube growth process parameters, namely the radii of the initial carbon nanotube patterns, the temperatures of the carbon nanotube patterns, and the energies of the incident carbon atoms. The simulation results provide an understanding of the roles played by these parameters in the fabrication of carbon nanotubes from an atomic perspective. It is shown that carbon nanotube patterns with small radii tend to form close-capped ends, while patterns with larger radii tend to promote lifted-up growth. Furthermore, the effect of pattern temperature is more obvious in the case of larger radii carbon nanotube patterns, in which disordered structures are evident at low pattern temperatures. Finally, it is shown that incident atoms with higher energies not only form unstable bonds with other carbon atoms, but may also destroy the covalent bonds of previously deposited carbon atoms. The present results provide a valuable insight into the promotion of close-capped nanotubes or lifted-up growth during the fabrication of carbon nanotubes.