FULLERENE NANOWIRES

A method has been found which produces nanowires in high yield. These wires are cylindrical single-walled fullerenes: hollow carbon tubes 1. 2-1.4 nm in diameter, >20 mu m in length, constructed of a single hexa gonally-bonded graphene sheet wrapped into a cylinder, with hemispheri cal endcaps involving 6 pentagons. They are produced by laser vaporiza tion of a composite rod of graphite with 1-2 atom percent of a catalys t such as 1/1 Ni/Co, inside a quartz tube at 1200 degrees C, in a 1 cm sec(-1) flow of argon at 500 Torr. The yield is greater than 50% of a ll the carbon vaporized. The wires are found to be aligned to form rop es of 10-100 parallel tubes held together in a closed-packed hexagonal array by van der Waals forces. The ropes are often found with overall length greater than 0.1 mm. Due to their expected high electrical con ductivity, especially when doped with metals either down the hollow in side region or on the outside, intercalated in the triangular gaps bet ween the adjacent tubes, these new materials may provide the first sou rce of wires on the nanometer scale whose electrical conduction is tru ly metallic. It may also be possible to make them much longer.