Carbon-onion thin-film synthesis onto silica substrates

A three-step technique devoted to the synthesis of pure carbon-onion thin f ilms deposited onto silica substrates has been developed. Carbon onions hav e been synthesized into silver thin films deposited on silica substrates by using 120 keV carbon ion implantations at 500 degrees C. After silver was removed by thermal annealing, pure carbon-onion thin films can be deposited onto silica substrates. The carbon onions thus obtained show an almost per fect spherical shape, their mean size varying with the implanted fluence. T he possibility of recovering a carbon onion powder using this new procedure is discussed, thus opening the way to study some carbon-onion properties w hich are still unknown. (C) 2000 Elsevier Science B.V. All rights reserved.