Modeling of particulate coagulation in low pressure plasmas

Kortshagen, Uwe; Bhandarkar, Upendra

doi:10.1103/physreve.60.887

Cited by 193 publications

(183 citation statements)

References 54 publications

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“…Generally, with increasing gas pressure (meaning collision frequency) the transferred energy increases for z << f, exhibits a maximum at f = z, and decreases for z >> f [9,66,67]. Most of the theoretical considerations on electrical charging of particles, on coagulation, or selective particle heating have been developed for non-thermal low pressure RF plasmas [47,[68][69][70][71]. Analogous considerations for microwave plasmas are seldom, but exist.…”

Section: Energy Transfer In a Microwave Plasmamentioning

confidence: 99%

“…Whereas in the beginning of research activity in this field mainly feasibility of all kind of materials was in the focus of research, later on also theoretical considerations on microwave plasmas combined with a deeper understanding of the processes occurring in the plasma, and the interaction between different species in the plasma were of interest in the several groups [46][47][48][49][50]. Finally, in the last decade the properties and the application potential of the resulting materials have increased very much in interest [20,[51][52][53][54][55][56][57][58][59][60].…”

Section: Microwave Plasma Synthesis Of Particulate Matter In the Histmentioning

confidence: 99%

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Microwave Plasma Synthesis of Materials—From Physics and Chemistry to Nanoparticles: A Materials Scientist’s Viewpoint

Szabó

Schlabach

2014

Inorganics

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Abstract:In this review, microwave plasma gas-phase synthesis of inorganic materials and material groups is discussed from the application-oriented perspective of a materials scientist: why and how microwave plasmas are applied for the synthesis of materials? First, key players in this research field will be identified, and a brief overview on publication history on this topic is given. The fundamental basics, necessary to understand the processes ongoing in particle synthesis-one of the main applications of microwave plasma processes-and the influence of the relevant experimental parameters on the resulting particles and their properties will be addressed. The benefit of using microwave plasma instead of conventional gas phase processes with respect to chemical reactivity and crystallite nucleation will be reviewed. The criteria, how to choose an appropriate precursor to synthesize a specific material with an intended application is discussed. A tabular overview on all type of materials synthesized in microwave plasmas and other plasma methods will be given, including relevant citations. Finally, property examples of three groups of nanomaterials synthesized with microwave plasma methods, bare Fe 2 O 3 nanoparticles, different core/shell ceramic/organic shell nanoparticles, and Sn-based nanocomposites, will be described exemplarily, comprising perspectives of applications.

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Section: Energy Transfer In a Microwave Plasmamentioning

confidence: 99%

Section: Microwave Plasma Synthesis Of Particulate Matter In the Histmentioning

confidence: 99%

Microwave Plasma Synthesis of Materials—From Physics and Chemistry to Nanoparticles: A Materials Scientist’s Viewpoint

Szabó

Schlabach

2014

Inorganics

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“…Kortshagen and Bhandarkar solved the so-called general dynamic equation, adopted from aerosol physics, in a 0D model, to obtain the particle size distribution by coagulation [34]. The latter approach, but in 1D, was also adopted by De Bleecker et al [35].…”

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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“…First, Si atoms are clusterized and the cluster grows to a few nanometers in the plasma in the first ~ 100 ms. After that, the particles start to coagulate with each other by Coulomb attractive force between negatively and positively charged particles, and rapidly grow to a size of 50-60 nm. Finally, the coagulation process stops, and the particles continue to grow by molecular sticking as in this stage almost all of the particles are charged negatively [26].…”

Section: Growth Kinetics Of Nanoparticles In a Plumementioning

confidence: 99%

“…In the Ar gas ambience Cn/Cn + may grow up to a nanometer size particle in plume due to impingement of a lot of Cn/Cn + (n = 1-3). However, in the Ar plasma ambience the mechanism of enhancement of the particle growth could be examined taking into account the following discussion made in SiH4 plasma CVD [23][24][25][26], since no information on carbon is available.…”

Section: Growth Kinetics Of Nanoparticles In a Plumementioning

confidence: 99%

Preparation of carbon nanoparticles by plasma-assisted pulsed laser deposition method—size and binding energy dependence on ambient gas pressure and plasma condition

et al. 2002

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Nanometer-size carbon particles were prepared on a Si substrate using pulsed laser deposition (PLD) assisted by radio frequency (RF) Ar plasma and were compared with ones prepared by PLD in vacuum and Ar gas. In both the plasma and gas ambiences, experiments were carried out in Ar pressure pAr ranging from 0.13 to 13 Pa. The particle size increased as pAr increased. However, the size obtained in the RF Ar plasma was approximately 1.5 times larger than that prepared in the Ar gas.An X-ray photoelectron spectroscopy (XPS) analysis revealed that the carbon film 2 covered by the particles was in an amorphous state. The sp 3 /sp 2 carbon ratio of the film was evaluated by deconvolution of XPS carbon (1s) spectra into three components, which are attributed to diamond (sp 3 ), graphite (sp 2 ) and carbon oxide components. The highest sp 3 /sp 2 ratio was 0.4 in the Ar gas and Ar plasma at pAr = 0.13 Pa. The sp 3 /sp 2 ratio decreases monotonously, as the particle size increases. The ratio obtained in the Ar plasma is larger than that in the Ar gas. The effects of pAr and plasma for nanoparticle characteristic are discussed.

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Modeling of particulate coagulation in low pressure plasmas

Cited by 193 publications

References 54 publications

Microwave Plasma Synthesis of Materials—From Physics and Chemistry to Nanoparticles: A Materials Scientist’s Viewpoint

Microwave Plasma Synthesis of Materials—From Physics and Chemistry to Nanoparticles: A Materials Scientist’s Viewpoint

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

Preparation of carbon nanoparticles by plasma-assisted pulsed laser deposition method—size and binding energy dependence on ambient gas pressure and plasma condition

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