Isotopic effects in hydrocarbon formation due to low-energy H+/D+ impact on graphite

Mech, B.V.; Haasz, A.A.; Davis, J.W.

doi:10.1016/s0022-3115(98)00035-x

Cited by 136 publications

(181 citation statements)

References 20 publications

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“…Measurements were made using residual gas analysis; data from [26]. Temperature dependent methane yields for pure carbon [27] are shown for comparison (solid line). The dotted line is a least square fit to the experimental data.…”

Section: Resultsmentioning

confidence: 99%

“…Based on this assumption, the yield near RT appears to be approximately 5×10 -3 CD 4 /D + [26]. Although the temperature dependence of CD 4 production obtained in [26] does not agree with the yields for pure carbon [27] (solid line in Figure 5(a)), the trend is similar to that observed by Balden et al [25]. Evidently, the chemistry of the mixed W-C surface differs from that of pure graphite and needs further investigation.…”

Section: Carbon Chemical Erosion From the Mixed Surfacementioning

confidence: 92%

“…In order to compare the CD 4 production levels obtained in [26] with methane yields for pure graphite [27], the measured production rates in [26] were normalized by the D + flux incident on the specimen. The derived 'apparent' yield represents an upper limit due to the inclusion of possible background contributions.…”

Section: Carbon Chemical Erosion From the Mixed Surfacementioning

confidence: 99%

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An overview of sputtering-related processes occurring at mixed surfaces formed by simultaneous C+ and D+ irradiation of W

Bizyukov

Krieger

Lee

et al. 2012

Journal of Nuclear Materials

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This paper reviews the interaction of carbon and deuterium ions with tungsten leading to the formation of mixed W-C-D surfaces. This projectile-target system is prone to synergistic effects, which are dependent on the presence of both projectile species. The erosion of the surface is governed by both kinematic effects and effects related to elevated surface temperature. It is found that the kinematics can be well described by available models of ionsurface interactions based on binary-collision approximations. The temperature-dependent processes include: chemical erosion, diffusion, erosion at elevated temperatures and radiation-enhanced sublimation. The effects of these processes, in particular their influence on the carbon content of the mixed W-C surface, have been studied experimentally. These experimental results and their implications for fusion applications are discussed here.2

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Section: Resultsmentioning

confidence: 99%

Section: Carbon Chemical Erosion From the Mixed Surfacementioning

confidence: 92%

Section: Carbon Chemical Erosion From the Mixed Surfacementioning

confidence: 99%

See 1 more Smart Citation

An overview of sputtering-related processes occurring at mixed surfaces formed by simultaneous C+ and D+ irradiation of W

Bizyukov

Krieger

Lee

et al. 2012

Journal of Nuclear Materials

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“…51 The erosion yield (10 À3 -10 1 ) depends furthermore on the ion energy and incident ion flux and, all else being equal, is higher for a-C:H than for graphite. 1,10,14,16,18,40,45,47,48 The fourth and last mechanism explained here is swift chemical sputtering, which first came to light via numerical modelling of very high hydrogen fluxes (up to 10 29 m À2 s À1 ) incident on an a-C:H surface. [52][53][54][55] An incident hydrogen radical enters the space occupied by a carbon-carbon bond.…”

Section: Amorphous Carbon Etch Mechanismsmentioning

confidence: 92%

“…10 Previous studies of carbon etching -with ion energies between 10 eV and 5 keV -have established several etch mechanisms in literature. [11][12][13][14][15][16][17][18] Two of those mechanisms, i.e. chemical sputtering and ion-assisted chemical erosion, describe a synergistic effect in the etch rate when simultaneously exposing a-C:H to both radicals and ions (see also Sec.…”

Section: Introductionmentioning

confidence: 99%

Synergistic etch rates during low-energetic plasma etching of hydrogenated amorphous carbon

Hansen

Weber

Colsters

et al. 2012

Journal of Applied Physics

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The etch mechanisms of hydrogenated amorphous carbon thin films in low-energetic (<2 eV) high flux plasmas are investigated with spectroscopic ellipsometry. The results indicate a synergistic effect for the etch rate between argon ions and atomic hydrogen, even at these extremely low kinetic energies. Ion-assisted chemical sputtering is the primary etch mechanism in both Ar/H2 and pure H2 plasmas, although a contribution of swift chemical sputtering to the total etch rate is not excluded. Furthermore, ions determine to a large extent the surface morphology during plasma etching. A high influx of ions enhances the etch rate and limits the surface roughness, whereas a low ion flux promotes graphitization and leads to a large surface roughness (up to 60 nm).

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Tight-Binding Atomistic Simulations of Hydrocarbon Sputtering by Hyperthermal Ions in Tokamak Divertors

Krasheninnikov

Salonen

Nordlund

et al. 2002

Contrib. Plasma Phys.

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Recent empirical potential simulations [5] explain from an atomistic point of view the mechanisms of the erosion of carbon‐based fusion reactor walls by low‐energy hydrogen ions coming from the plasma. However, it is not quite clear yet to what extent the quantum‐mechanical effects are important for an adequate description of the erosion. Making use of tight‐binding molecular dynamics, which accounts for the quantum‐mechanical nature of impinging particle‐surface interaction, we re‐examine the low‐energy erosion mechanisms by simulating the ion‐assisted bond breaking in simple model systems like carbon dimers and by modeling sputtering from realistic hydrogenated carbon slabs. Our simulations confirm the empirical potential results on the low energy bond‐breaking mechanism, and help one to differentiate between the different mechanisms of the erosion.

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Isotopic effects in hydrocarbon formation due to low-energy H+/D+ impact on graphite

Cited by 136 publications

References 20 publications

An overview of sputtering-related processes occurring at mixed surfaces formed by simultaneous C+ and D+ irradiation of W

An overview of sputtering-related processes occurring at mixed surfaces formed by simultaneous C+ and D+ irradiation of W

Synergistic etch rates during low-energetic plasma etching of hydrogenated amorphous carbon

Tight-Binding Atomistic Simulations of Hydrocarbon Sputtering by Hyperthermal Ions in Tokamak Divertors

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