Modeling carbon nanotube growth on the catalyst-substrate surface subjected to reactive plasma

Abstract

The paper presents a theoretical model to study the growth of the carbon nanotube (CNT) on the catalyst substrate surface subjected to reactive plasma. The charging rate of the CNT, kinetics of electron, ions and neutral atoms, the growth rate of the CNT because of diffusion and accretion of ions on the catalyst nanoparticle inclusion of the issue of the plasma sheath is undertaken in the present model. Numerical calculations on the effect of ion density and temperature and the substrate bias on the growth of the CNT have been carried out for typical glow discharge plasma parameters. It is found that the height of CNT increases with the ion density of carbon ions and radius of CNT decreases with hydrogen ion density. The substrate bias also affects the growth rate of the CNT. The field emission characteristics from the CNTs can be analyzed from the results obtained.

Theoretical modeling of temperature dependent catalyst-assisted growth of conical carbon nanotube tip by plasma enhanced chemical vapor deposition process

“…Ion collection current to the CNT(both conical tip and cylindrical surface) 19 n iBconcts þ n iBcysct or n iAconcts þ n iAcysct 19. Neutral collection current to the CNT(both conical tip and cylindrical surface) 19 n Bconcts þ n Bcysct or n Aconcts þ n Acysct 20. Electron collection current to the CNT(both conical tip and cylindrical surface) 19 n econcts þ n ecysct …”

“…Neutral collection current to the CNT(both conical tip and cylindrical surface) 19 n Bconcts þ n Bcysct or n Aconcts þ n Acysct 20. Electron collection current to the CNT(both conical tip and cylindrical surface) 19 n econcts þ n ecysct …”

“…I pA and I pB are the ionization energies of atoms A (acetylene) and B (hydrogen), respectively (Ref. 19). T a is the ambient temperature, e is the emissivity of the material of the catalyst, and r is the Stefan-Boltzmann constant.…”

“…Desorption flux of acetylene ions and hydrogen ions from catalyst-substrate surface 19 J desorptionj ¼ n ij À e ai k B T ij 18. Ion collection current to the CNT(both conical tip and cylindrical surface) 19 n iBconcts þ n iBcysct or n iAconcts þ n iAcysct 19. Neutral collection current to the CNT(both conical tip and cylindrical surface) 19 n Bconcts þ n Bcysct or n Aconcts þ n Acysct 20.…”

“…Accretion of neutral acetylene atoms to the conical tip of CNT 19 c C2H2 pr 2 conct n C2H2conct16. Adsorption flux of acetylene ions and hydrogen ions to catalyst-substrate surface19 …”