Si doping enhances the thermal stability of diamond-like carbon through reductions in carbon-carbon bond length disorder
Autor: | Filippo Mangolini, Robert W. Carpick, Jennifer R. Lukes, J. B. McClimon, James Hilbert |
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Rok vydání: | 2018 |
Předmět: |
Materials science
Diamond-like carbon Silicon Doping chemistry.chemical_element 02 engineering and technology General Chemistry 010402 general chemistry 021001 nanoscience & nanotechnology 01 natural sciences 0104 chemical sciences Amorphous solid Bond length chemistry Chemical engineering General Materials Science Thermal stability ReaxFF 0210 nano-technology Carbon |
Zdroj: | Carbon. 131:72-78 |
ISSN: | 0008-6223 |
DOI: | 10.1016/j.carbon.2018.01.081 |
Popis: | Low thermal stability is a major limitation of diamond-like carbon (DLC) films, especially amorphous hydrogenated carbon (a-C:H) films, inhibiting their use in several applications. Adding silicon and oxygen to a-C:H increases thermal stability, but mechanisms for this increase are unknown. Reactive molecular dynamics (MD) simulations using the ReaxFF potential were performed on undoped a-C:H and a-C:H containing Si and O (a-C:H:Si:O). As in experiments, the simulated a-C:H:Si:O demonstrated increased thermal stability compared to a-C:H. Atomistic thermal degradation pathways were examined to understand the origins of the enhanced thermal stability of a-C:H:Si:O compared to a-C:H. The primary thermal degradation pathway in undoped a-C:H was the breaking of tensile strained C-C bonds resulting in a transformation of sp3 to sp2-hybridized carbon. The presence of Si suppresses this mechanism by decreasing the frequency of occurrence of highly strained C-C bonds in the unannealed structure. This is due to the longer C-Si equilibrium bond length compared to C-C bonds, which allows the Si-doped films to accommodate higher structural disorder. |
Databáze: | OpenAIRE |
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