Double and single vacancies differently affect the conductance of C nanotubes so that the exact knowledge of the abundance of these defects was mandatory for an unambiguous interpretation of irradiation-induced changes in nanotube conductance. Concentrations of defects produced by Ar ions were calculated by using the molecular dynamics method, combined with kinetic Monte Carlo simulations. Carefully taking into account the annealing of defects, it was shown that the ratio of single to double vacancies had a minimum at ion energies of about 0.5keV and that the ratio saturated towards a constant value at high ion energies.

Relative Abundance of Single and Double Vacancies in Irradiated Single-Walled Carbon Nanotubes. A.Tolvanen, J.Kotakoski, A.V.Krasheninnikov, K.Nordlund: Applied Physics Letters, 2007, 91[17], 173109