ELECTRON-MICROSCOPY, GROWTH AND DEFECTS OF CARBON NANOTUBES

The carbon nanotubes formed at the cathode of the electric are discharge apparatus used to produce fullerenes were imaged by high resolution transmission electron microscopy. Besides nanotubes, two other phases which are frequently the main components in the deposits were detected: polyhedral carbons and a microporous carbon. The nanotubes are a few nanometers to a few tens of nanometers in diameter and up to a few micrometers in length. They are often closed by two or three parallel sheets bended with a limited number of angle values. These values were correlated with typical defects occurring during the growth of aromatic layers. Primary defects with one atom missing (pentagon) or in excess (heptagon) and also more complex combinations of pentagons and heptagons were identified. We deduced that the general conditions for closing the nanotubes are given by Euler's rule, i.e. the presence at each tip of six pentagons.