NANOCARBONS FORMED UNDER AC ARC-DISCHARGE

Large quantities of a wide range of carbon net forms have been synthesized and observed by a TEM in a deposit obtained by ac are discharge in an argon ambient between close proximity electrodes. The forms differ in size and arrangement; these include closed or open end tubes, spiral tube cares, boomerang, single and double cone, arch, spherical with a large hollow core, spherical ordered structures, spherical amorphous, and a variety of polyhedral forms. The step by step growth process is discussed. Initially a two-dimensional carbon net grows spatially. Successive concentric layers grow temporally externally and internally to the initial surface. Due to the weak interaction between the atoms from the different layers, quite often the upper layers do not copy the initial form of the carbon net. The defects that arise define the nature of the deviations from the initial carbon net, the preferred spatial C-C bond angle, and the mechanism of growth characteristic for the structures.