Dissociative adsorption has been widely simplified as part of the vapor–liquid–solid (VLS) growth
model. We found that the addition of specific carrier gases can critically modify the growth rate and
growth density of multiwall carbon nanotubes (MWNTs). These results were explained by
dissociative adsorption of C2H2 molecules and a solid-core VLS growth model. Based on these
integrated mechanisms, vertically aligned MWNTs were grown with an initial growth rate as high
as ,800 mm/h. This efficient growth process results at temperature and C2H2 partial pressures at
which the decomposition and segregation rates of carbon are balanced. Appropriate use of carrier
gas is one of the factors that could facilitate efficient and continuous growth of carbon nanotubes in
the future.