Diagnostic studies of species concentrations in a capacitively coupled RF plasma containing CH<sub>4</sub>-H<sub>2</sub>-Ar

Gathen, Volker Schulz-von der; Röpcke, J.; Gans, Timo; Käning, M.; Lukas, C; Döbele, H. F.

doi:10.1088/0963-0252/10/3/318

Cited by 40 publications

(32 citation statements)

References 56 publications

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“…It has been suggested that hydrocarbon radicals, such as CH x (x = 1, 2, 3), are very important species. [41][42][43][44] As reported previously, the formation energy of single vacancies (SV) in graphene is very large (about 7.5 eV). [45,46] Thus, it is very probable that interaction with reactive species can effectively lead to the healing of SV to restore a perfect graphene structure.…”

Section: Introductionmentioning

confidence: 54%

Role of Hydrocarbon Radicals CH_x (x=1, 2, 3) in Graphene Growth: A Theoretical Perspective

Wang

Xiao

2012

ChemPhysChem

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Many outstanding properties of graphene are blocked by the existence of structural defects. Herein, we propose an important healing mechanism for the growth of graphene, which is produced via plasma-enhanced chemical vapor decomposition (PECVD), that is, the healing of graphene with single vacancies by decomposed CH(4) (hydrocarbon radical CH(x), x=1, 2, 3). The healing processes undergo three evolutionary steps: 1) the chemisorption of the hydrocarbon radicals, 2) the incorporation of the C atom of the hydrocarbon radicals into the defective graphene, accompanied by the adsorption of the leaving H atom on the graphene surface, 3) the removal of the adsorbed H atom and H(2) molecule to generate the perfect graphene. The overall healing processes are barrierless, with a huge released heat of 530.79, 290.67, and 159.04 kcal mol(-1), respectively, indicative of the easy healing of graphene with single vacancies by hydrocarbon radicals. Therefore, the good performance of the PECVD method for the generation of graphene might be ascribed to the dual role of the CH(x) (x=1, 2, 3) species, acting both as carbon source and as defect healer.

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Section: Introductionmentioning

confidence: 54%

Role of Hydrocarbon Radicals CH_x (x=1, 2, 3) in Graphene Growth: A Theoretical Perspective

Wang

Xiao

2012

ChemPhysChem

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“…The most straightforward measurement of these parameters with Langmuir probe (LP) is unfortunately not possible due to the formation of insulating layer on the probe tip and other methods has to be used. Microwave interferometry has been used instead to measure electron densities in CH 4 and C 2 H 2 containing plasmas [57,84,85]. Alternatively, a plasma absorption probe [86,87] can be used and it has been applied to measure electron density in Ar/C 2 H 2 plasma containing dust particles [88].…”

Section: Experimental Techniques For Study Of Pcrsmentioning

confidence: 99%

Plasma-chemical reactions: low pressure acetylene plasmas

Benedikt¹

2010

J. Phys. D: Appl. Phys.

136

137

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Reactive plasmas are a well-known tool for material synthesis and surface modification. They offer a unique combination of non-equilibrium electron and ion driven plasma chemistry, energetic ions accelerated in the plasma sheath at the plasma–surface interface, high fluxes of reactive species towards surfaces and a friendly environment for thermolabile objects. Additionally, small negatively charged clusters can be generated, because they are confined in the positive plasma potential. Plasmas in hydrocarbon gases, and especially in acetylene, are a good example for the discussion of different plasma-chemical processes. These plasmas are involved in a plethora of possible applications ranging from fuel conversion to formation of single wall carbon nanotubes. This paper provides a concise overview of plasma-chemical reactions (PCRs) in low pressure reactive plasmas and discusses possible experimental and theoretical methods for the investigation of their plasma chemistry. An up-to-date summary of the knowledge about low pressure acetylene plasmas is given and two particular examples are discussed in detail: (a) Ar/C2H2 expanding thermal plasmas with electron temperatures below 0.3 eV and with a plasma chemistry initiated by charge transfer reactions and (b) radio frequency C2H2 plasmas, in which the energetic electrons mainly control PCRs.

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“…The IRMA system has been applied successfully in several studies of molecular phenomena in plasmas, e.g. [38,62,68,70,94,128,129].…”

Section: The Irma Systemmentioning

confidence: 99%

Application of mid-infrared tuneable diode laser absorption spectroscopy to plasma diagnostics: a review

Röpcke

Lombardi

Rousseau

et al. 2006

Plasma Sources Sci. Technol.

Self Cite

102

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Within the last decade mid-infrared absorption spectroscopy over a region from 3 to 17µm and based on tuneable lead salt diode lasers, often called tuneable diode laser absorption spectroscopy or TDLAS, has progressed considerably as a powerful diagnostic technique for in situ studies of the fundamental physics and chemistry in molecular plasmas. The increasing interest in processing plasmas containing hydrocarbons, fluorocarbons, organo-silicon and boron compounds has led to further applications of TDLAS because most of these compounds and their decomposition products are infrared active. TDLAS provides a means of determining the absolute concentrations of the ground states of stable and transient molecular species, which is of particular importance for the investigation of reaction kinetic phenomena. Information about gas temperature and population densities can also be derived from TDLAS measurements. A variety of free radicals and molecular ions have been detected by TDLAS. Since plasmas with molecular feed gases are used in many applications such as thin film deposition, semiconductor processing, surface activation and cleaning, and materials and waste treatment, this has stimulated the adaptation of infrared spectroscopic techniques to industrial requirements. The recent development of quantum cascade lasers (QCLs) offers an attractive new option for the monitoring and control of industrial plasma processes. The aim of the present paper is threefold: (i) to review recent achievements in our understanding of molecular phenomena in plasmas, (ii) to report on selected studies of the spectroscopic properties and kinetic behaviour of radicals and (iii) to describe the current status of advanced instrumentation for TDLAS in the mid-infrared.

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Diagnostic studies of species concentrations in a capacitively coupled RF plasma containing CH₄-H₂-Ar

Cited by 40 publications

References 56 publications

Role of Hydrocarbon Radicals CH_x (x=1, 2, 3) in Graphene Growth: A Theoretical Perspective

Role of Hydrocarbon Radicals CH_x (x=1, 2, 3) in Graphene Growth: A Theoretical Perspective

Plasma-chemical reactions: low pressure acetylene plasmas

Application of mid-infrared tuneable diode laser absorption spectroscopy to plasma diagnostics: a review

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Diagnostic studies of species concentrations in a capacitively coupled RF plasma containing CH4-H2-Ar

Cited by 40 publications

References 56 publications

Role of Hydrocarbon Radicals CHx (x=1, 2, 3) in Graphene Growth: A Theoretical Perspective

Role of Hydrocarbon Radicals CHx (x=1, 2, 3) in Graphene Growth: A Theoretical Perspective

Plasma-chemical reactions: low pressure acetylene plasmas

Application of mid-infrared tuneable diode laser absorption spectroscopy to plasma diagnostics: a review

Contact Info

Product

Resources

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Diagnostic studies of species concentrations in a capacitively coupled RF plasma containing CH₄-H₂-Ar

Role of Hydrocarbon Radicals CH_x (x=1, 2, 3) in Graphene Growth: A Theoretical Perspective

Role of Hydrocarbon Radicals CH_x (x=1, 2, 3) in Graphene Growth: A Theoretical Perspective