COBALT-CATALYZED GROWTH OF CARBON NANOTUBES WITH SINGLE-ATOMIC-LAYERWALLS

CARBON exhibits a unique ability to form a wide range of structures. I n an inert atmosphere it condenses to form hollow, spheroidal fulleren es1-4. Carbon deposited on the hot tip of the cathode of the arc-disch arge apparatus used for bulk fullerene synthesis will form nested grap hitic tubes and polyhedral particles5-8. Electron irradiation of these nanotubes and polyhedra transforms them into nearly spherical carbon 'onions'9. We now report that covaporizing carbon and cobalt in an arc generator leads to the formation of carbon nanotubes which all have v ery small diameters (about 1.2 nm) and walls only a single atomic laye r thick. The tubes form a web-like deposit woven through the fullerene -containing soot, giving it a rubbery texture. The uniformity and sing le-layer structure of these nanotubes should make it possible to test their properties against theoretical predictions10-13.