Microwave plasma-based direct synthesis of free-standing N-graphene

Цыганов, Д. Л.; Bundaleska, N.; Dias, Ana; Henriques, J.; Felizardo, E.; Abrashev, M. V.; Kissovski, J.; Rego, A.M. Botelho do; Ferraria, Ana Maria; Tatarova, E.

doi:10.1039/c9cp05509f

Cited by 30 publications

(24 citation statements)

References 43 publications

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“…Considering the diffusion of carbon species into colder zones of the plasma reactor, the formation of solid carbon nuclei in the colder nucleation zones of the plasma reactor was analyzed from the model results. A correlation between C 2 radicals and C atom number densities and the sp 3 /sp 2 ratio in the freestanding graphene sheets was observed with the hypothesis that the assembly of planar sp 2 carbons is dominated by the presence of C 2 radicals [80]. To explain the temperaturedependent graphene growth kinetics in pulsed CVD on Ni film substrates, Puretzky et al developed a model involving generation of carbon atoms on the metal surface resulting from the feedstock gas pulse, carbon diffusion in the bulk of the film, and diffusion to surface defects or graphene crystallites within a shallow subsurface layer of the film [82].…”

Section: Introductionmentioning

confidence: 84%

“…Trinsoutrot et al proposed a chemical mechanism for methane pyrolysis on copper foil within a computational fluid dynamics (CFD) model to investigate the role of the gas phase in graphene formation [79]. The team led by Prof. E. Tartarova studied the synthesis of freestanding graphene sheets from the decomposition of ethanol vapor in atmospheric-pressure microwave argon plasma [80,81]. Their model considers the decomposition of ethanol/argon/hydrogen in microwave plasma through 57 species and 394 homogeneous reactions.…”

Section: Introductionmentioning

confidence: 99%

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Graphene synthesis by microwave plasma chemical vapor deposition: analysis of the emission spectra and modeling

Pashova

Hinkov

Aubert

et al. 2019

Plasma Sources Sci. Technol.

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In this article, we report on some of the fundamental chemical and physical processes responsible for the deposition of graphene by microwave plasma-enhanced chemical vapor deposition (PECVD). The graphene is grown by plasma decomposition of a methane and hydrogen mixture (CH 4 /H 2) at moderate pressures over polycrystalline metal catalysts. Different conditions obtained by varying the plasma power (300-400 W), total pressure (10-25 mbar), substrate temperature (700-1000°C), methane flow rate (1-10 sccm) and catalyst nature (Co-Cu) were experimentally analyzed using the in situ optical emission spectroscopy (OES) technique to assess the species rotational temperature of the plasma and the H-atom relative concentration. Then, two modeling approaches were developed to analyze the plasma environment during graphene growth. As a first approximation, the plasma is described by spatially averaged bulk properties, and the species compositions are determined using kinetic rates in the transient zero-dimensional (0D) configuration. The advantage of this approach lies in its small computational demands, which enable rapid evaluation of the effects of reactor conditions and permit the identification of dominant reactions and key species during graphene growth. This approach is useful for identifying the relevant set of species and reactions to consider in a higher-dimensional model. The reduced chemical scheme was then used within the self-consistent two-dimensional model (2D) to determine auto-coherently the electromagnetic field, gas and electron temperatures, heavy species, and electron and ion density distributions in the reactor. The 0D and 2D models are validated by comparison with experimental data obtained from atomic and molecular emission spectra.

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Section: Introductionmentioning

confidence: 84%

Section: Introductionmentioning

confidence: 99%

Graphene synthesis by microwave plasma chemical vapor deposition: analysis of the emission spectra and modeling

Pashova

Hinkov

Aubert

et al. 2019

Plasma Sources Sci. Technol.

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“…Electrical properties are a key issue for a wide spectrum of applications. Generally, it should be mentioned that the plasma synthesized materials, including graphene, are characterized by the standpoint of their structural properties, and chemical content of flakes [ 30 , 48 , 49 , 50 , 51 ]. Here, we study the plasma jet-assisted synthesized graphene materials aimed at the development of electronic devices fabricated by printing techniques on a flexible substrate, providing pervasive, light-weight, and cost-effective devices.…”

Section: Discussionmentioning

confidence: 99%

Graphene Flakes for Electronic Applications: DC Plasma Jet-Assisted Synthesis

et al. 2020

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The possibility of graphene synthesis (the bottom-up approach) in plasma and the effective control of the morphology and electrical properties of graphene-based layers were demonstrated. Graphene flakes were grown in a plasma jet generated by a direct current plasma torch with helium and argon as the plasma-forming gases. In the case of argon plasma, the synthesized graphene flakes were relatively thick (2–6 nm) and non-conductive. In helium plasma, for the first time, graphene with a predominance of monolayer flakes and high conductivity was grown in a significant amount using an industrial plasma torch. One-dimensional (1D) flow modeling shows that the helium plasma is a less charged environment providing the formation of thinner graphene flakes with low defect density. These flakes might be used for a water-based suspension of the graphene with PEDOT:PSS (poly(3,4-ethylenedioxythiophene): polystyrene sulfonate) composite to create the structures employing the 2D printing technologies. Good structural quality, low layer resistance, and good mechanical strength combined with the ability to obtain a large amount of the graphene powder, and to control the parameters of the synthesized particles make this material promising for various applications and, above all, for sensors and other devices for flexible electronics and the Internet of things ecosystem.

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“…It has been reported, for the first time, application of microwave-driven plasmas in atmospheric pressure for the single-step production of N-doped high quality free-standing graphene sheets [24][25][26][27][28][29][30][31] . The advantages of this approach are in its reproducibility and ability to control morphological, structural and functional properties of the synthesized material.…”

mentioning

confidence: 99%

“…The end-result is production of graphene sheets, highly doped by nitrogen (up to 8%at. ), collected with ~ 40% in the form of single atomic layers, with very low-content of oxygen (< 1%) and high-ratio of sp 2 /sp 3 carbons (~ 15) [24][25][26][27][28][29][30][31] . Coating of stainless steel and copper by this material has recently been performed using electrophoretic deposition, which reduced SEY of samples from about 2.4 to 1.0.…”

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confidence: 99%

Prospects for microwave plasma synthesized N-graphene in secondary electron emission mitigation applications

Bundaleska

Dias

Bundaleski

et al. 2020

Sci Rep

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the ability to change the secondary electron emission properties of nitrogen-doped graphene (n-graphene) has been demonstrated. to this end, a novel microwave plasma-enabled scalable route for continuous and controllable fabrication of free-standing n-graphene sheets was developed. High-quality N-graphene with prescribed structural qualities was produced at a rate of 0.5 mg/min by tailoring the high energy density plasma environment. Up to 8% of nitrogen doping levels were achieved while keeping the oxygen content at residual amounts (~ 1%). The synthesis is accomplished via a single step, at atmospheric conditions, using ethanol/methane and ammonia/methylamine as carbon and nitrogen precursors. The type and level of doping is affected by the position where the n-precursor is injected in the plasma environment and by the type of precursors used. importantly, N atoms incorporated predominantly in pyridinic/pyrrolic functional groups alter the performance of the collective electronic oscillations, i.e. plasmons, of graphene. For the first time it has been demonstrated that the synergistic effect between the electronic structure changes and the reduction of graphene π-plasmons caused by N doping, along with the peculiar "crumpled" morphology, leads to sub-unitary (< 1) secondary electron yields. N-graphene can be considered as a prospective low secondary electron emission and plasmonic material. The development of low Secondary Electron Emission (SEE) materials is of great importance for modern technologies, overarching from space applications (e.g. telecommunication satellites) to particle accelerators. For instance, a significant potential difference between the dielectric and conductive part of satellites can arise due to a difference in their secondary electron yields (SEYs) induced by cosmic rays, igniting discharges that can disrupt normal operation or even destroy the equipment. Additionally, in the presence of an alternating electric field and under resonant conditions, secondary electrons can accelerate to high enough velocities to strike the material and free additional electrons, which can then be accelerated and so forth, leading to an exponential increase of the number of free electrons, a process known as multipacting 1-14. This phenomenon is responsible for the formation of electron clouds (e-clouds) in particle accelerators, which affect particle beam trajectories and introduce beam instabilities. In addition, electron bombardment of the tube walls introduces pressure rise and additional heat loads of these cryogenic systems. All this makes e-cloud effect the major limitation of beam luminosity of modern particle accelerators. Similarly, e-cloud formed in microwave generators of satellite communication devices affects electron trajectories and introduces noise in the communication systems.

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Microwave plasma-based direct synthesis of free-standing N-graphene

Abstract: Scheme of ethanol/ammonia plasma driven decomposition pathways considering injection of the nitrogen precursor in “hot” and “mild” plasma zone.

Cited by 30 publications

References 43 publications

Graphene synthesis by microwave plasma chemical vapor deposition: analysis of the emission spectra and modeling

Graphene synthesis by microwave plasma chemical vapor deposition: analysis of the emission spectra and modeling

Graphene Flakes for Electronic Applications: DC Plasma Jet-Assisted Synthesis

Prospects for microwave plasma synthesized N-graphene in secondary electron emission mitigation applications

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