The results of numerical simulations, optical emission spectroscopy (OES), and quadrupole mass spectrometry (QMS) of inductively coupled Ar/CH4/H2 plasmas in the plasma enhanced chemical vapor deposition (PECVD) of self-assembled vertically aligned carbon nanostructures (CNs) are presented. A spatially averaged (global) discharge model is developed to study the densities and fluxes of the radical neutrals and charged species, the effective electron temperature, methane conversion factor under various growth conditions. The numerical results show a remarkable agreement with the OES and QMS data. It is found that the deposited cation fluxes in the PECVD of CNs generally exceed those of the radical neutrals.

Zero-dimensional, space-averaged global models of argon dust-free and dusty afterglow plasmas are developed, which describe the time behaviour of electron n e(t) and Ar* metastable n m(t) densities. The theoretical description is based on the assumption that the free electron density is smaller than the dust charge density. In pure argon, fairly good agreement with the experimentally measured densities and their decay times in the afterglow is obtained when the electron energy loss term to the chamber walls is included in the electron energy balance equation. In dusty plasma afterglow, the agreement between theory and experiment is less satisfactory. The calculated metastable density is 3 times smaller than the measured one and the electron decay is much faster in the late afterglows. The difference should probably arise from the assumption that the electron energy distribution function is Maxwellian. Different sources of secondary electrons in the dusty plasma afterglow are analysed. Comparison of the model with experimental results of argon dusty plasma suggests that the metastable pooling could be the source of the experimentally observed electron density increase in the early afterglow but electron generation from metastable–dust interactions cannot be fully discarded.

The properties of an Ar/C 2 H 2 dusty plasma (ion, electron and neutral particle densities, effective electron temperature and dust charge) in glow and afterglow regimes are studied using a volumeaveraged model and the results for the glow plasma are compared with mass spectrometry measurements. It is shown that dust particles affect essentially the properties of glow and afterglow plasmas. Due to collection of electrons and ions by dust particles, the effective electron temperature, the densities of argon ions and metastable atoms are larger in the dusty glow plasma comparing with the dust-free case, while the densities of most hydrocarbon ions and acetylene molecules are smaller. Because of a larger density of metastable argon atoms and, as a result, of the enhancement of electron generation in their collisions with acetylene molecules, the electron density in the afterglow dusty plasma can have a peak in its time-dependence. The results of numerical calculations are in a good qualitative agreement with experimental results.

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The growth of single-walled carbon nanotubes (SWCNTs) in plasma-enhanced chemical vapor deposition (PECVD) is studied using a surface diffusion model. It is shown that at low substrate temperatures (⩽1000K), the atomic hydrogen and ion fluxes from the plasma can strongly affect nanotube growth. The ion-induced hydrocarbon dissociation can be the main process that supplies carbon atoms for SWCNT growth and is responsible for the frequently reported higher (compared to thermal chemical vapor deposition) nanotube growth rates in plasma-based processes. On the other hand, excessive deposition of plasma ions and atomic hydrogen can reduce the diffusion length of the carbon-bearing species and their residence time on the nanotube lateral surfaces. This reduction can adversely affect the nanotube growth rates. The results here are in good agreement with the available experimental data and can be used for optimizing SWCNT growth in PECVD.

A complex low-pressure argon discharge plasma containing dust grains is studied using a Boltzmann equation for the electrons and fluid equations for the ions. Local effects, such as the spatial distribution of the dust density and external electric field, are included, and their effect on the electron energy distribution, the electron and ion number densities, the electron temperature, and the dust charge are investigated. It is found that dust particles can strongly affect the plasma parameters by modifying the electron energy distribution, the electron temperature, the creation and loss of plasma particles, as well as the spatial distributions of the electrons and ions. In particular, for sufficiently high grain density and/or size, in a low-pressure argon glow discharge, the Druyvesteyn-like electron distribution in pristine plasmas can become nearly Maxwellian. Electron collection by the dust grains is the main cause for the change in the electron distribution function.

The time-dependent properties of an Ar/C2H2 dusty plasma (neutral, ion and electron densities, effective electron temperature and dust charge) are studied using a volume-averaged model for conditions corresponding to experiments on nanoparticle growth. The calculated density evolution for C2H2, H2 and C4H2 molecules are compared with time-resolved measurement of the mass peaks of the neutral species and the effects of the dust density on the plasma properties are analyzed. Time evolutions of the main positive and negative ions are also obtained thanks to the calculations. As a consistency check the time-dependence of the dust radius is also obtained numerically, assuming that an increase of the dust radius is due to deposition of hydrocarbon ions and C2H radicals on the surface of dust particles. It is shown that for conditions corresponding to the experiment, the ions are the main contributor to the particle growth. The calculated dust growth rate is compared to the time-dependence of the dust particle size obtained in the experimental measurements. The results of the numerical calculations are found to be in a good qualitative agreement with the experimental data.