New pathways for nanoparticle formation in acetylene dusty plasmas: a modelling investigation and comparison with experiments

Mao, Ming; Benedikt, Jan; Consoli, Angelo; Bogaerts, Annemie

doi:10.1088/0022-3727/41/22/225201

Cited by 63 publications

(120 citation statements)

References 69 publications

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“…Diacetylene is of interest for astronomy-it is a potential precursor for the H−C≡C−C≡C − anion, recently detected in interstellar space [1,2] and it was detected in the upper layers of planetary atmospheres (Titan, Uranus) [3,4], where free electrons also occur. Electron collisions with diacetylene are of interest also in technological plasmas [5,6]. Diacetylene is an important intermediate in flames [7,8], in particular, for the formation of soot [9].…”

Section: Introductionmentioning

confidence: 99%

Absolute angle-differential vibrational excitation cross sections for electron collisions with diacetylene

et al. 2011

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Absolute vibrational excitation cross sections were measured for diacetylene (1,3-butadiyne). The selectivity of vibrational excitation reveals detailed information about the shape resonances. Excitation of the C≡C stretch and of double quanta of the C−H bend vibrations reveals a 2 u resonance at 1 eV (autodetachment width ∼30 meV) and a 2 g resonance at 6.2 eV (autodetachment width 1-2 eV). There is a strong preference for excitation of even quanta of the bending vibration. Excitation of the C−H stretch vibration reveals σ * resonances at 4.3, 6.8, and 9.8 eV, with autodetachment widths of ∼2 eV. Detailed information about resonances permits conclusions about the mechanism of the dissociative electron attachment.

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Section: Introductionmentioning

confidence: 99%

Absolute angle-differential vibrational excitation cross sections for electron collisions with diacetylene

et al. 2011

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“…Because the calculated densities of these species were fairly high, it was suggested that aromatic compounds might play a role as growth precursors for nanoparticles in hydrocarbon plasmas [47]. Another improvement of this model was presented by Ming et al [48]. Indeed, based on a comparison with experimental data, some new mechanisms for negative ion formation and growth, arising from dissociative electron attachment of (linear and branched) hydrocarbons (C 2n H 2 ), were proposed.…”

Section: Modeling Of Nanoparticle Formation In Plasmasmentioning

confidence: 99%

Computer modelling of the plasma chemistry and plasma-based growth mechanisms for nanostructured materials

Bogaerts¹,

Eckert²,

Mao³

et al. 2011

J. Phys. D: Appl. Phys.

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In this review paper, an overview is given of different modeling efforts for plasmas used for the formation and growth of nanostructured materials. This includes both the plasma chemistry, providing information on the precursors for nanostructure formation, as well as the growth processes itself. We limit ourselves to carbon (and silicon) nanostructures. Examples of the plasma modeling comprise nanoparticle formation in silane and hydrocarbon plasmas, as well as the plasma chemistry giving rise to carbon nanostructure formation, such as (ultra)nanocrystalline diamond ((U)NCD) and carbon nanotubes (CNTs). The second part of the paper deals with the simulation of the (plasma-based) growth mechanisms of the same carbon nanostructures, i.e., (U)NCD and CNTs, both by mechanistic modeling and detailed atomistic simulations. IntroductionLow temperature plasmas are playing an increasingly important role for the formation and growth of nanostructures and nanostructured materials (e.g., [1][2][3][4][5][6][7]). To improve the performance of these plasma growth processes, a good insight is desired in the plasma and in the interaction with the growing nanostructures. This insight can be obtained by experimental research, but the latter is not always straightforward, in view of the small dimensions of the nanomaterials and the possible disturbance of the plasma characteristics, e.g., when introducing a probe. Therefore, computer simulations can be very useful to assist in the experimental developments.In the present paper, we will give an overview of different modeling efforts that have been presented in the literature for plasmas used for nanostructure formation. This includes two different aspects. First, a thorough understanding of the plasma behavior is needed. This comprises background gas flow and heating (i.e., fluid dynamics), gas breakdown, transport and heating of the electrons and the so-called heavy particles, as well as the plasma chemistry, i.e., creation and destruction of the various plasma species by chemical reactions. Modeling of the plasma chemistry can give indications on which species are important precursors for the growth of nanostructured materials and how the plasma operating conditions can be tuned to optimize the growth process. Therefore, in this paper we will mainly focus on the plasma chemistry modeling. Several plasma modeling approaches exist in literature, such as analytical models, zero-dimensional (0D) chemical kinetics simulations, fluid models (describing the chemical kinetics as well as fluid dynamics), solving the Boltzmann transport equation, Monte Carlo (MC) and particle-in-cell (PIC)-MC simulations, as well as hybrid methods, combining the above (e.g., MC + fluid) models. For describing the plasma chemistry, the 0D chemical kinetics approach is often applied, as it can take into account a large number of different species and reactions without too much computational effort. However, it assumes a spatially uniform plasma composition and does not consider transport of the plasm...

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“…The dominance of the species with an even carbon atom number is a distinct feature of C 2 H 2 discharges. One-dimensional fluid simulations of capacitive C 2 H 2 plasmas have been performed for nanoparticle formation by De Bleecker et al [46] and Mao et al [47] in our group. The results showed that negative ions played a key role during the nanoparticle formation.…”

Section: The Plasma Chemistry For Cnt/cnf Growthmentioning

confidence: 99%

“…All data needed to calculate the diffusion coefficients of all the plasma species included in the models were adopted from [44] and [47]. For ions both motilities and diffusion coefficients are considered.…”

Section: Diffusion and Wall Deposition Lossesmentioning

confidence: 99%

See 1 more Smart Citation

Investigating the plasma chemistry for the synthesis of carbon nanotubes/nanofibres in an inductively coupled plasma enhanced CVD system: the effect of different gas mixtures

Mao¹,

Bogaerts²

2010

J. Phys. D: Appl. Phys.

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To cite this version:M Mao, A Bogaerts. Investigating the plasma chemistry for the synthesis of carbon nanotubes/nanofibres in an inductively coupled plasma enhanced CVD system: the effect of different gas mixtures. Journal of Physics D: Applied Physics, IOP Publishing, 2010, 43 (20) Abstract. A hybrid model, called the Hybrid Plasma Equipment Model (HPEM) was used to study an inductively coupled plasma in gas mixtures of H 2 or NH 3 with CH 4 or C 2 H 2 used for the synthesis of carbon nanotubes or carbon nanofibers (CNTs/CNFs). The plasma properties are discussed for the different gas mixture at low and moderate pressure, and the growth precursors for CNTs/CNFs are analyzed. It is found that C 2 H 2 , C 2 H 4 , and C 2 H 6 are the predominant molecules in CH 4 containing plasmas beside the feedstock gas, and serve as carbon sources for CNT/CNF formation. On the other hand, long chain hydrocarbons are observed in C 2 H 2 containing plasmas. Furthermore, the background gases CH 4 and C 2 H 2 show a different decomposition rate with H 2 or NH 3 addition at moderate pressures.

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New pathways for nanoparticle formation in acetylene dusty plasmas: a modelling investigation and comparison with experiments

Cited by 63 publications

References 69 publications

Absolute angle-differential vibrational excitation cross sections for electron collisions with diacetylene

Absolute angle-differential vibrational excitation cross sections for electron collisions with diacetylene

Computer modelling of the plasma chemistry and plasma-based growth mechanisms for nanostructured materials

Investigating the plasma chemistry for the synthesis of carbon nanotubes/nanofibres in an inductively coupled plasma enhanced CVD system: the effect of different gas mixtures

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