Mechanism of chemical erosion of sputter-deposited C:H films

Schenk, A.; Biener, J.; Winter, Bernd; Lutterloh, C.; Schubert, U. A.; Küppers, J.

doi:10.1063/1.108182

Cited by 39 publications

(28 citation statements)

References 12 publications

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“…On heating, HAC evolves toward a protographitic material through loss of hydrogen, desorption of hydrocarbon molecules, and the growth of sp 2 hybridized bonded aromatic rings (Schenk et al 1992). This can be followed in the absorption spectrum through the weakening of the 3.4 and 6.9 m bands and the enhancement of spectral features such as those at 3.…”

Section: Discussionmentioning

confidence: 99%

The Decomposition of Hydrogenated Amorphous Carbon: A Connection with Polycyclic Aromatic Hydrocarbon Molecules

Scott

Duley

1996

The Astrophysical Journal

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We have produced thin solid films of hydrogenated amorphous carbon (HAC) by vapor deposition in vacuum and have investigated the structure and infrared spectra of these materials under conditions in which they are at the point of decomposition. We find that the IR absorption spectrum of HAC under these conditions contains all the major spectral components seen in emission in nebulae. In addition, high-resolution scanning tunneling microscopy of HAC prior to decomposition reveals protographitic islands with dimensions 11-5 nm showing that polycyclic aromatic hydrocarbon (PAH)-like molecular groups evolve from HAC. These experimental results suggest for the first time how PAHs and HAC may be related and how PAH molecules could evolve from HAC in regions of high excitation. The material produced as HAC decomposes is a very low density carbonaceous "aerogel" consisting primarily of these aromatic protographitic clusters in a weakly connected friable network. These protographitic clusters may be the source of interstellar graphite grains.

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Section: Discussionmentioning

confidence: 99%

The Decomposition of Hydrogenated Amorphous Carbon: A Connection with Polycyclic Aromatic Hydrocarbon Molecules

Scott

Duley

1996

The Astrophysical Journal

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“…Both the general appearance of the spectra and the measured D/C ratios of the films suggest a possible presence of a polymerlike structure. 20,21 Film thicknesses were measured using a Dektak IIA surface profilometer. Thicknesses of 220Ϯ20 nm were obtained for both the unexposed and 18 O 2 -exposed films.…”

Section: Composition Structure and Thickness Of A-c:d Filmsmentioning

confidence: 99%

Thermo-oxidative erosion of amorphous hydrogenated carbon films

Haasz

Chiu

Pierre

et al. 1996

Journal of Vacuum Science &Amp; Technology A: Vacuum, Surfaces, and Films

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Chemical sputtering measurements in Tore Supra by aftershot mass spectrometry outgassing studies J. Vac. Sci. Technol. A 15, 2597 (1997 Fabrication of cross-linked polymer shells for inertial confinement fusion experiments J. Vac. Sci. Technol. A 15, 683 (1997) Tritium permeation and inventory in an international thermonuclear experimental reactor divertor J. Vac. Sci. Technol. A 15, 169 (1997) Measurements of tritium retention and removal on the Tokamak Fusion Test ReactorAmorphous C:D ͑or C:H͒ films were deposited on the inner surface of a spherical ultrahigh vacuum chamber by means of a direct current glow discharge in a ϳ75% D 2 ͑or H 2 ͒ and ϳ25% CD 4 ͑CH 4 ͒ gas mixture. Laser Raman spectroscopy analysis of the film exhibited the absence of a diamond peak at 1334.3 cm Ϫ1 . The general appearance of the spectra was indicative of a polymerlike film. Upon exposure of the C:D film to 18 O 2 , almost all of the released deuterium was seen to be in the D 2 18O chemical form, with less than 1% released as D 2 . C 18 O 2 was observed to be the main C-containing reaction product of the 18 O 2 exposure. No methane release was detected. x-ray photoelectron spectroscopy and secondary ion mass spectroscopy analyses of the films indicated the appearance of carbonyl groups ͑ϾCvO͒ and an increase in the concentration of hydroxyl groups ͑-COD͒ due to surface oxidation. The generally accepted scheme for simple thermal oxidation of hydrocarbon polymers was used to provide a plausible reaction mechanism leading to emissions of the reaction products D 2 O, CO 2 , and CO.

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“…The erosion occurs via both physical sputtering (ejection of atoms from the target due to collisional momentum transfer) and chemical erosion of hydrocarbon compounds which takes place also at impact energies below the threshold energy of physical sputtering. Several mechanisms for the chemical erosion of carbon by hydrogen have been presented in the literature [4][5][6][7][8][9][10][11].…”

Section: Introductionmentioning

confidence: 99%

Overview of the Atomistic Modeling of the Chemical Erosion of Carbon

Salonen

2004

Physica Scripta

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Understanding the mechanisms of the chemical erosion of carbon by hydrogen is of great importance for the application and development of plasma-facing materials, as well as the macroscopic scale modeling of plasma-surface interactions in fusion devices. In the recent years there has been a number of atomistic modeling studies, namely molecular dynamics and electronic structure calculations, on these processes. This article is an overview of these investigations, with comparison to experimental measurements as well as current theoretical understanding of the chemical erosion of carbon. Implications of the modeling are discussed along with an outlook on future studies.Ã

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Mechanism of chemical erosion of sputter-deposited C:H films

Cited by 39 publications

References 12 publications

The Decomposition of Hydrogenated Amorphous Carbon: A Connection with Polycyclic Aromatic Hydrocarbon Molecules

The Decomposition of Hydrogenated Amorphous Carbon: A Connection with Polycyclic Aromatic Hydrocarbon Molecules

Thermo-oxidative erosion of amorphous hydrogenated carbon films

Overview of the Atomistic Modeling of the Chemical Erosion of Carbon

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