Surface reactions on beryllium after carbon vapour deposition and thermal treatment

The Journal of Chemical Physics

Jacob

2008

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This paper investigates the reactivity of elemental carbon films deposited from the vapor phase with Fe and Ni substrates at room temperature. X-ray photoelectron spectroscopy (XPS) measurements are presented as a method for evaluating kinetic reaction data. Carbon films are deposited on different surface orientations representing geometries from a dense atom packing as in fcc (111), to an open surface structure, as in fcc (100). During annealing experiments several reactions are observed (carbon subsurface diffusion, carbide formation, carbide decomposition, and graphite ordering). These reactions and the respective kinetic parameters are analyzed and quantified by XPS measurements performed while annealing at elevated temperatures (620-820 K). The resulting activation barriers for carbon subsurface diffusion are compared with calculated values using the Density Functional Theory (DFT). The determined kinetic parameters are used to reproduce the thermal behavior of carbon films on nickel surfaces. PACS numbers: 81.05.J, 68.35.D, 71.15.M, 79.60, 82.20

Section: Introductionsupporting

confidence: 88%

Section: A Carbon Films After Room Temperature Deposition and Annealmentioning

confidence: 89%

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Carbon reaction and diffusion on Ni(111), Ni(100), and Fe(110): Kinetic parameters from x-ray photoelectron spectroscopy and density functional theory analysis

The Journal of Chemical Physics

Jacob

2008

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“…Films prepared under these conditions show a thin carbide layer at the adsorbate-metal interface and additionally elemental (not reacted) carbon. Such behavior was observed also on various other substrates [22][23][24][25][26]. Carbon film thick- nesses range from the submonolayer region up to several nanometers.…”

Section: Introductionsupporting

confidence: 52%

“…In addition, binding energy shifts are caused by processes like cluster size effects or surface rearrangements. In addition to Ni we investigate carbon films on W, Be, Ti and Si, as reported earlier [22][23][24][25]. The reactivity of carbon films depends on thermodynamic properties of the respective carbides.…”

Section: Introductionmentioning

confidence: 99%

Thermally induced reaction and diffusion of carbon films on Ni(111) and Ni(100)

2008

Surface Science

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Thin carbon films on Ni(111) and Ni(100) and the reactive and diffusive interactions between film and substrate are investigated using X-ray photoelectron spectroscopy (XPS). The carbon films are deposited from the vapor phase with the substrates at room temperature. After deposition the films contain mainly elemental carbon. Restricted only to the carbon-nickel interface carbidic carbon is observed. Carbon films of various thicknesses between 0.4 and 3.2 nm are investigated after thermal treatments up to 970 K. The C 1s signal intensities are used for chemical analysis, both in a qualitative and quantitative way. The initially formed carbide partially decomposes between 400 and 570 K. Additional carbide formation sets in again, combined with incipient carbon diffusion, at higher temperatures. Carbon diffusion into the bulk leads to a decreasing C 1s signal intensity until the carbon is almost completely lost into the bulk.

Formation of endothermic carbides on iron and nickel

2004

phys. stat. sol. (a)

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The formation of endothermic carbides on Fe and Ni is studied using X-ray photoelectron spectroscopy (XPS) by deposition of carbon films from the vapor phase and subsequent annealing steps. The reaction between carbon and metal substrates is measured by shifts in the C 1s photoelectron peaks. By comparison with two elementary carbon photoelectron energies determined from carbon films on unreactive Au substrates, a carbide peak in the C 1s spectra on reactive Fe and Ni substrates is identified. The carbides formed after deposition of carbon films at room temperature are located at the interface between carbon film and metal substrate. We report on the behavior of elementary carbon films with respect to film thickness and thermal treatment leading to carbide formation and carbon diffusion into the bulk.