Diagnostics and modeling of glow discharges by time-resolved IR absorption spectroscopy

Tanarro, Isabel; Arcos, Teresa de los; Domingo, Concepción; Herrero, Vı́ctor J.; Sanz, M. M.

doi:10.1016/s0042-207x(01)00338-4

Cited by 14 publications

(22 citation statements)

References 9 publications

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“…In order to estimate individual rate constants from experimental data, the time evolution of the different species during the ignition and the extinction of the discharge has proven much more useful than the steady state results [21]. Consequently, the time dependence of the concentration of the precursor in the fundamental and in some vibrational excited levels, as well as that of all the molecular products of the N 2 O plasma, were experimentally studied at different discharge modulation frequencies and different time scales, for the first time [22,23].…”

Section: Introductionmentioning

confidence: 99%

Characterization and modelling of the steady state and transients of modulated hollow cathode discharges of nitric oxide

Castillo

Herrero

Tanarro

2002

Plasma Sources Sci. Technol.

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This work describes a systematic experimental study and kinetic modelling of the steady state and the transients associated with the turn on and off of a NO hollow cathode discharge. The local charge density and mean electron energy have been determined with a double Langmuir probe. Time-resolved Fourier transform infrared spectroscopy and electron bombardment quadrupole mass spectrometry with ionisation by electron impact have been used to measure the gas temperature and the concentrations of the stable molecules present in the discharge: the precursor, NO, the major products, N 2 , O 2 , and the minor species NO 2 and N 2 O. Emission spectroscopy has been employed to study the time behaviour of the very reactive nitrogen and oxygen atoms. A model based on a reduced set of kinetic equations including electron dissociation, gas-phase reactions, and gas-surface processes gives a global account of the measured data. From the time resolved results, electron impact dissociation rate constants for some of the involved species under the conditions of the experiment are estimated. The present model is compared with that obtained in previous works on N 2 O plasmas.

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Section: Introductionmentioning

confidence: 99%

Characterization and modelling of the steady state and transients of modulated hollow cathode discharges of nitric oxide

Castillo

Herrero

Tanarro

2002

Plasma Sources Sci. Technol.

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“…Also, the surface loss probability in the stainless steel is larger for NH· than for N·; meanwhile, for CH 3 ·, it is much lower. All these Stainless steel [14] T = 300 K B = s = 10 À2 to 10 À4 a-C:H [15] Ion or H· bombardment B = 1.3 × 10 À3 /5 × 10 À3 /10 À2 Stainless steel [16] T = 300/340-380/420 K s = 10 À5 to 10 À6 . B = 4 × 10 À4 ; s = 1 × 10…”

Section: Productsmentioning

confidence: 99%

Surface effects on the diagnostic of carbon/nitrogen low‐pressure plasmas studied by differentially pumped mass spectrometry

2014

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In this work, the characterization of the species produced in reactive plasmas by differentially pumped mass spectrometry is addressed. A H2/CH4/N2 mixture (90 : 5 : 5) was fed into a direct current glow discharge and analysed by conventional and cryo-trap assisted mass spectrometry. The gaseous mixture was chosen because of its particular relevance in the inhibition of tritium-rich carbon film deposition in fusion plasmas (scavenger technique) and in the deposition of amorphous hydrogenated carbon films by plasma-assisted chemical vapour deposition. Important changes in the composition of the detected species upon surface modification of the reactor walls (stainless steel or covered by an amorphous hydrogenated carbon layer) or in the way they are sampled (length and spatial configuration of the stainless steel duct) were detected. They are analysed in terms of radical formation and recombination on the reactor walls or into the sampling duct, thus providing some insight into the underlying chemistry. In general, when the reactor walls are covered by an amorphous hydrogenated carbon layer, more hydrocarbons are produced, but the radical production is lower and seem to be less reactive than in stainless steel. Also, two sources of oxygen contamination in the plasma have been identified, from the native oxide layer in stainless steel and from unintended water contamination in the chamber, which modify considerably the detected species.

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“…[75] In this way, a very characteristic periodic increase and decrease of dust density and average size has been found, even in non-modulated discharges, controlled by gravity. On the other hand, on/off plasma modulation, which controls in time the concentrations of shortlived species, allows the application of several of the former mentioned diagnostic techniques to time-resolved plasma studies, [76] which add valuable information on reaction coefficients and wall reaction probabilities [77] and opens new insights in deposition processes with minimum dust production. [78] Concerning plasma surface interactions, a recent simple method to determine surface loss probabilities employs a dismountable cavity with a small entrance slit exposed to the reactive species, [44] which allows a later study of the deposited materials in the internal surfaces.…”

Section: Diagnostic Techniquesmentioning

confidence: 99%

From Carbon Nanostructures to New Photoluminescence Sources: An Overview of New Perspectives and Emerging Applications of Low‐Pressure PECVD

Gordillo‐Vázquez¹,

Herrero²,

Tanarro³

2007

Chemical Vapor Deposition

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Low-pressure, plasma-enhanced (PE)CVD is a powerful and versatile technique that has been used for thin-film deposition and surface treatment since the early 1960s. However, it is only recently that it has been used in applications other than the different stages of microelectronic circuit fabrication. Now, PECVD is being used in emerging applications due to new materials and process requirements in a wide variety of areas, such as biomedical applications, solar cells, fuel cell development, fusion research, or the synthesis of silicon nanocrystals showing efficient photoluminescence, useful for future solid-state light sources. These new scenarios have stimulated further development of novel PECVD diagnostic techniques, together with fundamental experimental and theoretical studies aimed at a better understanding of some of the basic processes underlying the plasma/surface interaction. This paper gives an overview of some new research areas where PECVD is finding promising applications.

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Diagnostics and modeling of glow discharges by time-resolved IR absorption spectroscopy

Cited by 14 publications

References 9 publications

Characterization and modelling of the steady state and transients of modulated hollow cathode discharges of nitric oxide

Characterization and modelling of the steady state and transients of modulated hollow cathode discharges of nitric oxide

Surface effects on the diagnostic of carbon/nitrogen low‐pressure plasmas studied by differentially pumped mass spectrometry

From Carbon Nanostructures to New Photoluminescence Sources: An Overview of New Perspectives and Emerging Applications of Low‐Pressure PECVD

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