ABSTRACT
Amorphous carbon is an important material from the point of view of both physics and applications. In a broad sense it includes carbon grains composed of long-chain molecules and solid carbonaceous particles (present in interstellar molecular clouds and in certain cool old stars), graphitic and diamond cluster mixtures, carbon fibers, chars and cokes, glassy carbon, and diamond-like carbon (DLC). One interesting form of carbon called carbyne consists of sp-hybridized linear chains. There is evidence for its presence in nature in a stable form for millions of years, as well as in meteorites, meteoritic craters, and interstellar materials. There are speculations that it could have been the starting material for the creation of life on earth [1]. On the other hand, many new classes of carbon-based conducting solids are known as conducting polymers. The electrical conductivity is given by the motion of electrons or ions and their scattering. It was felt that undoped polymers are insulators and that polymers conduct only if they are doped. At present, some polymers are available, e.g., (SN),, that can conduct even without any doping. The conductivity in the polymeric backbone is governed by the availability of 7T electrons. One exception is the polyacetylene (CH)„ unit, whose conductivity of —103 S cm-1 is due to the propagation of solitons [2].
