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Plasma-enhanced chemical vapor deposition (PECVD) provides a low-temperature, highly-efficient, and catalyst-free route to fabricate graphene materials by virtue of the unique properties of plasma. In this paper, we conduct reactive molecular dynamics simulations to theoretically study the detailed growth process of graphene by PECVD at the atomic scale. Hydrocarbon radicals with different carbon/hydrogen (C/H) ratios are employed as dissociated precursors in the plasma environment during the growth process. The simulation results show that hydrogen content in the precursors significantly affects the growth behavior and properties of graphene ( e.g. , the quality of obtained graphene, which is indicated by the number of hexagonal carbon rings formed in the graphene sheets). Moreover, increasing the content of hydrogen in the precursors is shown to reduce the growth rate of carbon clusters, and prevent the formation of curved carbon structures during the growth process. The findings provide a detailed understanding of the fundamental mechanisms regarding the effects of hydrogen on the growth of graphene in a PECVD process.
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This content will become publicly available on July 1, 2026
Synthesis of high entropy boride in reactive MW-plasma environments: Enhanced reducing capability
We investigate the synthesis of the high entropy boride (HEB), MoNbTaVWB10, in a highly reactive environment facilitated by hydrogen feedgas in microwave plasma (MW plasma). Dissociation of molecular hydrogen to form copious amounts of atomic hydrogen allows efficient reduction of the metal oxide precursors with less excess boron needed for HEB formation than if an Ar-rich feedgas is used. This study demonstrates that hydrogen plasma promotes the hexagonal AlB2-type structure at temperatures as low as 1500C, achieving a predominantly single -phase structure at 1750C. In both environments, hardness and surface topography of the HEBs are measured, highlighting the enhanced effectiveness of the reactive feedgas in the synthesis process. XRD analysis confirms the enhanced reduction efficiency and phase purity facilitated by atomic hydrogen, while SEM/EDX reveals improved elemental uniformity and minimized vanadium sublimation. Compared to argon-rich plasma, hydrogen plasma results in larger grain sizes and reduced microstrain, underscoring its role in optimizing the microstructure and synthesis of HEBs. The findings show the advantages of a reactive synthesis environment for sustainable and efficient metallurgical process, enabling advanced material applications.
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- PAR ID:
- 10612032
- Publisher / Repository:
- Elsevier
- Date Published:
- Journal Name:
- Materials Chemistry and Physics
- Volume:
- 339
- Issue:
- C
- ISSN:
- 0254-0584
- Page Range / eLocation ID:
- 130712
- Subject(s) / Keyword(s):
- High entropy ceramics Atomic hydrogen Microwave plasma
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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