A surface and a gas-phase mechanism for the description of growth on the diamond(100) surface in an oxy-acetylene torch reactor

Abstract

Document VersionPublisher's PDF, also known as Version of Record (includes final page, issue and volume numbers) Please check the document version of this publication:• A submitted manuscript is the author's version of the article upon submission and before peer-review. There can be important differences between the submitted version and the official published version of record. People interested in the research are advised to contact the author for the final version of the publication, or visit the DOI to the publisher's website.• The final author version and the galley proof are versions of the publication after peer review.• The final published version features the final layout of the paper including the volume, issue and page numbers. Link to publication Citation for published version (APA):Okkerse, M., Croon, de, M. H. J. M., Kleijn, C. R., van den Akker, H. E. A., & Marin, G. B. M. M. (1998). A surface and a gas-phase mechanism for the description of growth on the diamond(100) surface in an oxyacetylene torch reactor. Journal of Applied Physics, 84(11), 6387-6398. DOI: 10.1063/1.368965 General rightsCopyright and moral rights for the publications made accessible in the public portal are retained by the authors and/or other copyright owners and it is a condition of accessing publications that users recognise and abide by the legal requirements associated with these rights.• Users may download and print one copy of any publication from the public portal for the purpose of private study or research.• You may not further distribute the material or use it for any profit-making activity or commercial gain • You may freely distribute the URL identifying the publication in the public portal ? Take down policyIf you believe that this document breaches copyright please contact us providing details, and we will remove access to the work immediately and investigate your claim. A gas-phase and a surface mechanism were developed, suitable for multidimensional simulations of diamond oxy-acetylene torch reactors. The gas-phase mechanism was obtained by reducing a 48 species combustion chemistry mechanism to a 27 species mechanism with the aid of sensitivity analysis. The surface mechanism for growth on monocrystalline ͑100͒ surfaces developed, was based on literature quantum-mechanical calculations by Skokov et al. It consists of 67 elementary reaction steps and 41 species, and contains CH 3 and C 2 H 2 as gas-phase growth precursors and atomic hydrogen and oxygen to etch carbon from the surface. The gas-phase and surface chemistry models were tested in one-dimensional simulations, yielding dependencies of the growth rate on feed composition and surface temperature that are in qualitative agreement with the experiments. A more detailed study of the surface chemistry showed that, compared to CH 3 , acetylene contributes very little to diamond growth. Furthermore, molecular and atomic oxygen do not affect the diamond surface as much as atomic hydrogen because of their low concentrations.

Influence of nitrogen on diamond growth in oxyacetylene combustion chemical vapor deposition

“…12 Through sensitivity analyses in one-dimensional flame simulations, we have reduced the original 48 species, 219 reactions mechanism to a 27 species, and 119 reactions mechanism. 13 Based on quantum-mechanical calculations by Skokov and co-workers, [47][48][49] we developed a surface reaction mechanism consisting of 67 elementary reactions between 41 adsorbed species, based on the so called mean field approximation. 13 It contains CH 3 and C 2 H 2 as gaseous growth precursors, and atomic hydrogen and oxygen as etching species.…”

“…13 Based on quantum-mechanical calculations by Skokov and co-workers, [47][48][49] we developed a surface reaction mechanism consisting of 67 elementary reactions between 41 adsorbed species, based on the so called mean field approximation. 13 It contains CH 3 and C 2 H 2 as gaseous growth precursors, and atomic hydrogen and oxygen as etching species. Earlier, 13,14 these two chemistry models were combined with one-dimensional ͑1D͒ and two-dimensional ͑2D͒ hydrodynamic model.…”

“…13 It contains CH 3 and C 2 H 2 as gaseous growth precursors, and atomic hydrogen and oxygen as etching species. Earlier, 13,14 these two chemistry models were combined with one-dimensional ͑1D͒ and two-dimensional ͑2D͒ hydrodynamic model. Figure 2 shows calculated isotherms and streamlines as calculated by the 2D model.…”

“…For diamond CVD from two-dimensional, conical oxyacetylene flames, we have previously presented detailed models for the homogeneous combustion chemistry and the heterogeneous diamond growth chemistry in Ref. 13, which we have subsequently combined with a two-dimensional hydrodynamic model for laminar oxyacetylene flames. 14 These models were validated against experimental data [15][16][17][18] on growth rates and concentration profiles of gas phase intermediates C, CH, and H, as a function of flame-tip-to-substrate distance and substrate temperature.…”

Two-dimensional simulation of an oxy-acetylene torch diamond reactor with a detailed gas-phase and surface mechanism

“…This model was successfully used for the simulation of oxyacetylene flames by Meeks et al 13 For a rich flame with a C 2 fuel, the mechanism cannot be reduced to the same size as for lean methane-air flames. In a previous study, 14 we reduced the mechanism to one consisting of 27 species and 119 reactions. This reduced mechanism is used in the present study.…”