Effect of plasma particles on synthesis of vertically-alligned carbon nanofibers in plasma-enhanced chemical vapor deposition

Summary form only given. We present a theoretical model describing a plasma-assisted growth of carbon nanofibers (CNFs), which involves two competing channels of carbon incorporation into stacked graphene sheets: via the surface diffusion and through the bulk of the catalyst particle (on top of a nanofiber) and accounts for a range of ion- and radical-assisted processes on the catalyst surface. Using this model, it is found that at low surface temperatures T_s, the CNF growth is indeed controlled by the surface diffusion. On the other hand, both the surface and bulk diffusion channels provide a comparable supply of carbon atoms to the stacked graphene sheets at elevated synthesis temperatures. It is also shown that at low T_s, insufficient for effective catalytic precursor decomposition, the plasma ions play a key role in production of carbon atoms on the catalyst surface. More importantly, these results quantify and explain a number of observations and semi- empirical conclusions of earlier experiments.