Valence band and core level photo-emission spectroscopy was used to study the changes produced by the bombardment of a single-wall carbon nanotube film by 3keV Ar+ ions at room temperature. At low ion doses (low defect density), an increase in spectral intensity near to the Fermi level was observed, associated with the formation of localized defect-related states. These states were acceptor-like, as indicated by a shift to lower binding energy for both valence band features and the C 1s core level. For large ion doses (high defect density), the spectral intensity near to the Fermi level decreased, valence-band features associated with delocalized π-bonding disappeared and a core-level component associated with sp3-bound carbon appeared. This behavior was attributed to amorphization of the single-walled carbon nanotube films and occurred at ion doses that were consistent with those that were theoretically predicted.

A Photoelectron Spectroscopy Study of Ion-Irradiation Induced Defects in Single-Wall Carbon Nanotubes. A.K.Chakraborty, R.A.J.Woolley, Y.V.Butenko, V.R.Dhanak, L.Šiller, M.R.C.Hunt: Carbon, 2007, 45[14], 2744-50