Catalytic mechanism of a Fe-Co bimetallic system for efficient growth of single-walled carbon nanotubes on SiSiO2 substrates

Abstract

Single-walled carbon nanotubes (SWCNTs)were grown on SiSi O2 substrates by catalytic chemical vapor deposition using ethanol as a carbon source. We found that a bimetallic catalyst, Fe-Co, worked efficiently in growing SWCNTs in contrast to Fe or Co catalyst only. The underlying mechanism was carefully studied by observing the catalyst-substrate interactions by transmission electron microscopy. It is shown that preferential diffusion of Fe into a Si O2 layer occurs in the bimetallic case, which suppresses aggregation of nanometer- sized Co particles that play key roles in growing SWCNTs. © 2006 American Institute of Physics.