A scanning tunnelling microscopic investigation of nanotube point defects (e.g. vacancies) created by ion irradiation was presented. The defects appeared as hillock-like features on the scanning tunnelling microscopic images. These defects were compared with similar features observed on the scanning tunnelling microscopic images of as-grown coiled C nanotubes. In this case the observed hillock-like features were attributed to the non-hexagonal C rings, which were responsible for the growth of bent and coiled nanotube structures. For irradiation, multi-walled C nanotubes produced by the arc-discharge method were dispersed on highly oriented pyrolitic graphite surface and irradiated with Ar+ ions of 30keV, using a low dose of 5 x 1011/cm2.

STM Imaging of Carbon Nanotube Point Defects. Z.Osváth, L.Tapasztó, G.Vértesy, A.A.Koós, Z.E.Horváth, J.Gyulai, L.P.Biró: Physica Status Solidi A, 2007, 204[6], 1825-9