Defects in single-walled carbon nanotubes introduced by low-energy electron irradiation at 8K were sensitively detected via the cryogenic thermal desorption of hydrogen molecules at 10 to 40K. The thermal desorption spectrum was found to change significantly with sample annealing at temperatures as low as 40 to 70K. Experimental results suggested that the H2 physisorption sites responsible for the defect peak at 28K were interstitial channel spaces between nanotubes closely packed in bundles which became more easily accessible after damage. It was also suggested that the disordering provided groove sites for H2 physisorption with a smaller binding energy, causing a damage-induced spectral component around 16K; slightly lower than the desorption peak at 20K that was observed in undamaged samples. The spectral change at 40 to 70K could be explained by the migration of adatoms at the low temperatures.

Electron-Stimulated Defect Formation in Single-Walled Carbon Nanotubes Studied by Hydrogen Thermal Desorption Spectroscopy. S.Arima, S.Lee, Y.Mera, S.Ogura, K.Fukutani, Y.Sato, K.Tohji, K.Maeda: Applied Surface Science, 2009, 256[4], 1196-9