Carbon nanotubes have been synthesized by chemical vapor deposition on grap
hite foil coated with stainless steel film as catalyst by magnetron sputter
ing. Annealing in hydrogen was used to convert the stainless steel film to
the needed catalyst particles that have a different composition from the in
itial stainless steel film due to phase segregation during annealing. The c
atalyst particle size increases with the increase of the initial stainless
steel film thickness. The outer diameter of the carbon nanotubes increases
dramatically with catalyst particle size, whereas the inner diameter increa
ses slightly first then remains roughly constant at about 7 nm. (C) 2001 El
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