Electron irradiation experiments in a transmission electron microscope were combined with kinetic Monte Carlo simulations in order to determine the mobility of interstitial carbon atoms in single-walled carbon nanotubes. Measurements were made of the irradiation dose necessary to cut nanotubes repeatedly, using a focused electron beam, as a function of the separation between the cuts and the temperature. As the cutting speed was related to the migration of displaced carbon atoms trapped inside the tube, and to their recombination with vacancies, information was obtained concerning the mobility of the trapped atoms and their migration barrier was estimated to be about 0.25eV. This constituted experimental confirmation of the markedly high mobility of interstitial atoms in carbon nanotubes.

The Diffusion of Carbon Atoms inside Carbon Nanotubes. G.Yanjie, J.Kotakoski, A.V.Krasheninnikov, K.Nordlund, F.Banhart: New Journal of Physics, 2008, 10, 023022