In situ measurements and modeling of carbon nanotube array growth kinetics during chemical vapor deposition

Puretzky, Alexander A.; Geohegan, David B.; Jesse, Stephen; Ivanov, Ilia N.; Eres, Gyula

doi:10.1007/s00339-005-3256-7

Cited by 311 publications

(390 citation statements)

References 34 publications

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“…By monitoring the thickness of nanotube forest films made by acetylene CVD by Fabry-Perot reflectivity [6,7], Puretzky et al found an initially accelerating growth rate and pointed out that it takes longer time to reach the maximum growth rate at higher temperature [7]. This is similar to what is observed here.…”

Section: Resultssupporting

confidence: 85%

The dynamics of the nucleation, growth and termination of single-walled carbon nanotubes from in situ Raman spectroscopy during chemical vapor deposition

2009

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The dynamics of the chemical vapor deposition (CVD) of single-walled carbon nanotubes (SWNTs) is extracted experimentally using in situ Raman spectroscopy. Nanotubes are grown using a thin À lm cobalt catalyst and À an ethanol precursor in a miniature hot walled reactor with optical access. Raman spectra at room temperature and at the growth temperature are compared for two growth temperatures. The evolution of the G-band, D-band, and radial breathing mode (RBM) is tracked at the growth temperature with time resolution of a few seconds. There are three identifiable phases in the evolution of the Raman signal intensity: an initial exponential increasing phase, a linear growth phase, and a saturation phase. In situ optical spectroscopy thus enables the study of nucleation, steady growth, and deactivation processes to be investigated separately in real time. The evolution curves for all bands (G, D, and RBM), when scaled, collapse onto the same curve, to within experimental uncertainty.

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Section: Resultssupporting

confidence: 85%

The dynamics of the nucleation, growth and termination of single-walled carbon nanotubes from in situ Raman spectroscopy during chemical vapor deposition

2009

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“…We have also recently confirmed the high temperatures and temperature gradients by in situ measurement of black-body radiation from the heater during growth. The optimum initial catalyst growth temperature (defined here as the temperature for which the maximum length is found) for multiwalled nanotubes is found to be 700-750 o C, in very good agreement with studies of the optimum growth temperature for similar catalyst and precursor materials in normal thermal CVD experiments [9,10].…”

Section: Temperature Modellingsupporting

confidence: 76%

“…Acetylene is a suitable precursor gas for the growth of arrays of vertically aligned multiwalled nanotube films [9]. Figure 3 shows an array grown on top of a Mo heater for the standard growth conditions and a current of 20 mA passing through the heater corresponding to a temperature on the order of 600-700 o C. A well-aligned array is produced with the length of the nanotubes decreasing towards the cooler zones at the heater edges.…”

Section: Arrays Of Vertically Aligned Multi-walled Nanotubesmentioning

confidence: 99%

Local heating method for growth of aligned carbon nanotubes at low ambient temperature

Dittmer

Mudgal

Nerushev

et al. 2008

Low Temperature Physics

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We use a highly localised resistive heating technique to grow vertically aligned multiwalled nanotube films and aligned single-walled nanotubes on substrates with an average temperature of less than 100 o C. The temperature at the catalyst can easily be as high as 1000 o C but an extremely high temperature gradient ensures that the surrounding chip is held at much lower temperatures, even as close as 1µm away from the local heater. We demonstrate the influence of temperature on the height of multi-walled nanotube films, illustrate the feasibility of sequential growth of single-walled nanotubes by switching between local heaters and also show that nanotubes can be grown over temperature sensitive materials such as resist polymer.PACS: 61.46.Fg Nanotubes.

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“…Table 1 summarizes the different mechanistic growth models published in recent years, indicating the processes included in each model, the reactor type (CVD or PE-CVD) and the simulation method. From this overview it is clear that the mechanistic models can be divided into three groups from simulation point of view, i.e., kinetic models [92][93][94][95][96][97][98][99], multiphysics, multiphase integrated models [100][101][102][103] and kinetic Monte Carlo (MC) models [104][105][106][107]. Puretzky and co-workers [92] presented a kinetic model for the CVD-based growth of vertically aligned nanotube arrays (VANTAs) from C 2 H 2 , based on in situ measurements.…”

Section: (B) Cnts and Related Structuresmentioning

confidence: 99%

“…A more detailed kinetic model [96] was developed by Naha and Puri, based on the models of [92,94,95]. The model included the impingement of C atoms, their adsorption and desorption on the catalyst surface, surface and bulk diffusion, and nucleation and separation of solid C in nanostructured form.…”

Section: (B) Cnts and Related Structuresmentioning

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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In situ measurements and modeling of carbon nanotube array growth kinetics during chemical vapor deposition

Cited by 311 publications

References 34 publications

The dynamics of the nucleation, growth and termination of single-walled carbon nanotubes from in situ Raman spectroscopy during chemical vapor deposition

The dynamics of the nucleation, growth and termination of single-walled carbon nanotubes from in situ Raman spectroscopy during chemical vapor deposition

Local heating method for growth of aligned carbon nanotubes at low ambient temperature

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

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