Effect of Gold catalytic layer thickness on growth of single-walled carbon nanotubes using thermal and plasma CVD

We carried out the carbon nanotubes (CNTs) growth from an Au catalyst with two different kinds of chemical vapor deposition (CVD) methods. In case of thermal CVD (TCVD), high quality single-walled carbon nanotubes (SWNTs) can be grown. On the other hand, only poorly crystallized CNTs are synthesized with plasma CVD (PCVD). Through the parametric investigations, it is found that the hydrogen gas supply which is known as a kind of growth support element in case of normal (Fe, Co, Ni) catalysts causes a significant decrease of SWNTs growth activity in case of Au. Since there is large number of atomic hydrogen reactants decomposed by energetic electrons in plasmas, This negative hydrogen reactants effect on the Au catalyst is supposed to be one possible reason for the unsuccessful growth of SWNTs from the Au catalyst with PCVD.