Effect of catalyst on growth behavior of carbon nanotubes synthesized by microwave heating thermal chemical vapor deposition process

Influence of morphology of Fe-catalyst on the microstructure and electron field emission properties of carbon nanotubes were systematically investigated. H-2-plasma treatment imposed a most significant effect on the morphology of Fe clusters. The 1200 W H-2-plasma treated Fe catalysts are nanosized.(40-80 nm), isolated, and uniformly distributed, which result in carbon nanotubes of highest purity and most density population, exhibiting the largest electron field emission capacity (J(e) = 3600 muA/cm(2) at 6V/mum applied field). Too low (1000 W) ortoo hi'h (1400 W) H-2-plasma treated Fe catalysts are interconnected or coarsened particulates, which result in large proportion of carbon soots, in addition to the carbon nanotubes. The electron field emission capacity of the films is thus markedly decreased. The prebaking process before H-2-plasma treatment also imposes a marked effect on those characteristics. These results imply that spin coating of Fe(OR)(3) is a simple and inexpensive method for producing catalyst of good quality, provided that the Fe(OR)(3) Was well pretreated. (C) 2003 American Vacuum Society.