Low pressure RF discharge in electronegative gases for plasma processing

Feoktistov, V. A.; Lopaev, Dmitry; Klopovsky, K. S.; Popov, A. M.; Popovicheva, O. B.; Rakhimov, A. T.; Рахимова, Т. В.

doi:10.1016/0022-3115(93)90301-e

Cited by 24 publications

(15 citation statements)

References 3 publications

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“…In these two DBD modes, electric field and electron density differ strongly from each other 11. Hence, these plasma parameters in the homogeneous and in the filamentary discharges are also spatially distributed resembling fine ‘patches’ or ‘patterns’ where drastic variations of these plasma parameters is observed between the two working electrodes in a DBD arrangement 25, 26…”

Section: Resultsmentioning

confidence: 99%

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Characterization of Dielectric Barrier Discharge (DBD) on Mouse and Histological Evaluation of the Plasma‐Treated Tissue

Rajasekaran

Opländer

Hoffmeister³

et al. 2011

Plasma Processes & Polymers

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Atmospheric‐pressure dielectric barrier discharge (DBD) in air is investigated for medical applications, especially for skin treatment. When the DBD was tested on mouse skin, a homogeneous discharge accompanied by filamentary microdischarges is observed. For characterization of the homogeneous discharge, averaged plasma parameters (namely electron density and electron velocity distribution function) and gas temperature are determined by optical emission spectroscopy, microphotography and numerical simulation. Chemical kinetics in the active plasma volume and in the afterglow is simulated. Fluxes of biologically useful molecules like nitric oxide (NO) and ozone reaching the treated surface and irradiation by UV photons are determined. Skin biopsy results show that DBD treatment causes no inflammation and no changes in the skin‐collagen.

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Section: Resultsmentioning

confidence: 99%

“…7 to no. 23 in Table 1 are calculated for gas temperature of 310 K using their temperature dependences,9, 22–29 while rate constants for the reactions no. 24 to no.31 are calculated based on the Arrhenius relation.…”

Section: Experimental Partmentioning

confidence: 99%

Characterization of Dielectric Barrier Discharge (DBD) on Mouse and Histological Evaluation of the Plasma‐Treated Tissue

Rajasekaran

Opländer

Hoffmeister³

et al. 2011

Plasma Processes & Polymers

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“…were negligible because of the extremely high rates of their deactivation under the experimental conditions that resulted in the fast destruction of these particles immediately after the discharge before the mixing zone [13]. A thin film of mercury oxide, HgO, was deposited on the inner side of the glass tube just behind the discharge area to remove O( 3 P) atoms and O 3 molecules which, as we know, are effective quenchers of O 2 (a 1 g ) [11,12,14].…”

Section: Methodsmentioning

confidence: 99%

“…Thus, under the gas discharge conditions the frequency of heterogeneous losses of O 2 ( 1 g ), and consequently the O 2 ( 1 g ) concentration, can strongly depend both on gas content and on discharge parameters. However, the discharge parameters themselves are some function of the metastable particle concentration at low pressures [5,6,13,40] due to secondary electron impacts and electron detachment from negative ions. This shows the necessity to account for heterogeneous processes with singlet oxygen on a detailed level for the correct understanding and representation of oxygen discharge kinetics.…”

Section: Model Of Heterogeneous O 2 ( 1 ∆ G ) Deactivation On a Glass...mentioning

confidence: 99%

Heterogeneous quenching of O₂(¹Delta_g) molecules in H₂:O₂mixtures

Klopovskiy

Lopaev

Попов

et al. 1999

J. Phys. D: Appl. Phys.

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Quenching of O2(1g) molecules both in the gas phase and on a reactor surface has been investigated in binary mixtures of hydrogen and oxygen by using the fast-flow quartz reactor and infrared emission spectroscopy. Rate constants of the O2(1g) deactivation by H2 and O2 at room temperature have been determined to be (1.5±0.5) 10-18 cm3 s-1 and (1.6±0.2) 10-18 cm3 s-1, respectively. Heterogeneous quenching of O2(1g) on quartz walls has been studied both in pure oxygen and in H2:O2 mixtures. A model of O2(1g) heterogeneous quenching in binary mixtures has been developed and has allowed us to describe all observed features of singlet oxygen kinetics. Active surface complexes formed by `chemisorbed' atomic oxygen and `physadsorbed' molecules of O2 and H2 are assumed to be responsible for the O2(1g) heterogeneous deactivation. It has been shown that the higher rate of O2(1g) quenching in pure oxygen is connected with a quasi-resonant transfer of the O2(1g) electronic excitation to physadsorbed oxygen molecules. The observed effect of the wall passivation by hydrogen is conditioned both by the absence of the similar resonance in the hydrogen surface complex and by the higher bond energy of H2 in this complex. Bond energies of O2 (3750±450 K) and H2 (4050±450 K) in the surface complexes have been determined from the model parameters by fitting calculations to experimental results.

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“…Investigation of the possibilities of obtaining a high yield of oxygen in a lower singlet state O 2 (a 1 g ) in a gas-discharge plasma is one of the problems with applications in lowtemperature plasma physics at present. As shown in [1][2][3][4][5][6][7][8][9], the use of radio frequency (RF) and microwave discharges (MW) for these purposes can be both perspective and more technological, especially in comparison, for example, with the non-self-sustained discharges excited by a powerful electron beam [11][12][13][14][15].…”

Section: Introductionmentioning

confidence: 99%

Singlet oxygen generation in O₂flow excited by RF discharge: II. Inhomogeneous discharge mode: plasma jet

Braginskiy¹,

Vasilieva²,

Kovalev³

et al. 2005

J. Phys. D: Appl. Phys.

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The transport dynamics of the metastable oxygen molecules O2(a 1Δg) and as well as O(3P) atoms in an oxygen flow excited by an RF discharge in a jet-mode has been investigated. The production and loss processes of these active species have been analysed by comparing experimental data with simulation results from a self-consistent model of the RF discharge jet-mode. It is shown that both atomic and singlet oxygen (SO) production occur mainly in the plasma jet areas outside the electrode zone. The interelectrode space provides the necessary boundary conditions for the plasma jet existence. The energy efficiency of O2(a 1Δg) production with RF discharge excitation of the oxygen flow was analysed in detail. It is demonstrated that the homogeneous discharge α -mode, where the O2(a 1Δg) excitation efficiency reaches ∼3–5%, is the optimal one for singlet oxygen pumping. The O2(a 1Δg) excitation efficiency drops below 1% at the transition from the α -mode to a jet-mode, though the maximum O2(a 1Δg) concentration is reached just in the jet-mode. At oxygen pressures less than 4 Torr and in the case of an RF discharge jet-mode with extremely fast gas cooling, it is possible to provide an SO yield over the threshold necessary for obtaining generation in an oxygen–iodine laser. However, it only results from the strong oxygen dissociation in the discharge. The O2(a 1Δg) excitation efficiency slightly increases with pressure owing to the decreasing mean electron energy in the discharge volume. With increasing pressure, O2(a 1Δg) quenching with the three-body recombination with atomic oxygen becomes more essential. The removal of atomic oxygen from the gas flow, for example by binding oxygen atoms with any molecular additives, is necessary for scaling the electro-discharged SO generator on pressure. The products of such ‘binding’ processes should not deactivate O2(a 1Δg). It is experimentally shown that the application of RF generators with a higher frequency (40 MHz instead of 13.56 MHz) allows us to increase the O2(a 1Δg) excitation efficiency by 30–40%.

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Low pressure RF discharge in electronegative gases for plasma processing

Cited by 24 publications

References 3 publications

Characterization of Dielectric Barrier Discharge (DBD) on Mouse and Histological Evaluation of the Plasma‐Treated Tissue

Characterization of Dielectric Barrier Discharge (DBD) on Mouse and Histological Evaluation of the Plasma‐Treated Tissue

Heterogeneous quenching of O₂(¹Delta_g) molecules in H₂:O₂mixtures

Singlet oxygen generation in O₂flow excited by RF discharge: II. Inhomogeneous discharge mode: plasma jet

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Low pressure RF discharge in electronegative gases for plasma processing

Cited by 24 publications

References 3 publications

Characterization of Dielectric Barrier Discharge (DBD) on Mouse and Histological Evaluation of the Plasma‐Treated Tissue

Characterization of Dielectric Barrier Discharge (DBD) on Mouse and Histological Evaluation of the Plasma‐Treated Tissue

Heterogeneous quenching of O2(1Deltag) molecules in H2:O2mixtures

Singlet oxygen generation in O2flow excited by RF discharge: II. Inhomogeneous discharge mode: plasma jet

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Heterogeneous quenching of O₂(¹Delta_g) molecules in H₂:O₂mixtures

Singlet oxygen generation in O₂flow excited by RF discharge: II. Inhomogeneous discharge mode: plasma jet