Self-Deactivation of Single-Walled Carbon Nanotube Growth Studied by in Situ Raman Measurements

In situ Raman measurements were used to investigate the kinetics and the self-deactivation of the growth of single-walled carbon nanotubes during catalytic chemical vapor deposition. The kinetics appear controlled by the mass-transport of the gaseous precursor at low precursor pressure and high temperature and by the catalytic decomposition of the precursor at high precursor pressure and low temperature. The initial growth rate and the lifetime display inversely correlated evolutions with the growth parameters. In addition, we measured the activation energy for the healing of defects during the growth and discuss it in comparison to the apparent activation energies measured for the initial growth rate and the lifetime. Our results support that the healing of the edge defects controls both the crystalline order and the growth lifetime.