NANOCARBONS FORMED UNDER AC ARC-DISCHARGE

Large quantities of a wide range of carbon net forms have been synthes ized and observed by a TEM in a deposit obtained by ac are discharge i n an argon ambient between close proximity electrodes. The forms diffe r in size and arrangement; these include closed or open end tubes, spi ral tube cares, boomerang, single and double cone, arch, spherical wit h a large hollow core, spherical ordered structures, spherical amorpho us, 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 internall y to the initial surface. Due to the weak interaction between the atom s 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 sp atial C-C bond angle, and the mechanism of growth characteristic for t he structures.