Ion ranges and irradiation-induced defects in multiwalled carbon nanotubes

Recent experiments on ion irradiation of carbon nanotubes have revealed a wealth of intriguing phenomena. However, in spite of the experimental progress, the production of irradiation-induced defects in multiwalled nanotubes (MWNTs) and their properties are not yet well understood. By employing molecular dynamics with analytical potentials we simulate irradiation of MWNTs with various noble-gas ions and calculate the ion ranges as a function of ion energy. We also use the conventional binary collision stochastic approach to estimate the ranges and compare the results obtained through the two methods. We further characterize the irradiation-induced defects which appear in MWNTs under both single ion impacts and high-dose bombardment. We finally study if, similarly to carbon onions, irradiation can give rise to transformations of nanotubes to nanodiamond rods and demonstrate that such transformations do not occur in MWNTs due to their tubular structure.