抄録
We present total energy calculations for open edge growth mechanisms of carbon nanotubes using the density functional theory. Energies of polygonal networks, such as the pentagon, hexagon and heptagon on the armchair edge are calculated. Activation energies of the diffusion of the carbon adatoms on both the armchair edge and the zigzag edge are also investigated. In addition, the carbon adatoms can be adsorbed on the wall of the nanotubes. Thus, we calculate the adsorption energies of the carbon adatoms on the nanotube wall. On the other hand, the pentagon network on the nanotube edge which is responsible for the nanotube closure must be annealed out to the hexagon network to maintain the open edge growth. We discuss annealing out of the polygonal networks such as the pentagon by calculations of the activation energies to incorporate the adatom into the polygonal networks. From these calculations, it is found that the adatoms on the nanotube wall diffusing toward the nanotube edge play an important role of the open edge growth of the nanotubes.
