Direct observation of single-walled carbon nanotube growth processes on SiO2 substrate by in situ scanning electron microscopy

We have observed the extension process of individual single-walled carbon nanotubes (SWCNTs) on SiO2 substrate during chemical vapor deposition using in situ scanning electron microscopy. Cobalt-filled apo-ferritin was used for dispersion of Co catalysts on the substrate, minimizing overlapping of SWCNTs grown. The growth of a SWCNT exhibited an incubation stage before nucleation, a growth stage with an average growth rate of 3–5 nm/s, and termination of extension after the growth stage. It is likely that catalyst migration at the SWCNT tip occurred for continued extension of SWCNTs on the substrate.