ELECTRON-MICROSCOPY, GROWTH AND DEFECTS OF CARBON NANOTUBES

The carbon nanotubes formed at the cathode of the electric are dischar ge 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 detecte d: polyhedral carbons and a microporous carbon. The nanotubes are a fe w nanometers to a few tens of nanometers in diameter and up to a few m icrometers in length. They are often closed by two or three parallel s heets bended with a limited number of angle values. These values were correlated with typical defects occurring during the growth of aromati c layers. Primary defects with one atom missing (pentagon) or in exces s (heptagon) and also more complex combinations of pentagons and hepta gons were identified. We deduced that the general conditions for closi ng the nanotubes are given by Euler's rule, i.e. the presence at each tip of six pentagons.