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Chemical vapour dep...
Chemical vapour deposition of molybdenum carbides: aspects of phase stability
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- Lu, J (författare)
- Department of Inorganic Chemistry, Ångström Laboratory, University of Uppsala, Box 538, S-751 21 Uppsala, Sweden
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- Hugosson, Håkan Wilhelm, 1972- (författare)
- Condensed Matter Theory Group, Department of Physics, University of Uppsala, Box 530, S-751 21, Uppsala, Sweden
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- Eriksson, O (författare)
- Condensed Matter Theory Group, Department of Physics, University of Uppsala, Box 530, S-751 21, Uppsala, Sweden
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- Nordström, L (författare)
- Condensed Matter Theory Group, Department of Physics, University of Uppsala, Box 530, S-751 21, Uppsala, Sweden
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- Jansson, U (författare)
- Department of Inorganic Chemistry, Ångström Laboratory, University of Uppsala, Box 538, S-751 21 Uppsala, Sweden
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(creator_code:org_t)
- Elsevier, 2000
- 2000
- Engelska.
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Ingår i: Thin Solid Films. - : Elsevier. - 0040-6090 .- 1879-2731. ; 370:1-2, s. 203-212
- Relaterad länk:
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https://urn.kb.se/re...
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https://doi.org/10.1...
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Abstract
Ämnesord
Stäng
- Thin films of different molybdenum carbides (δ-MoC1−x, γ′-MoC1−x and Mo2C) have been deposited from a gas mixture of MoCl5/H2/C2H4 at 800°C by CVD. The H2 content in the vapour has a strong influence on the phase composition and microstructure. Typically, high H2 contents lead to the formation of nanocrystalline δ-MoC1−x films while coarse-grained γ′-MoC1−x is formed with an H2-free gas mixture. This phase has previously only been synthesized by carburization of Mo in a CO atmosphere and it has therefore been considered as an oxycarbide phase stabilized by the presence of oxygen in the lattice. Our results, however, show that γ′-MoC1−x films containing only trace amounts of oxygen can be deposited by CVD. Stability calculations using a FP-LMTO method confirmed that the γ′-MoC1−x phase is stabilized by oxygen but that the difference in energy between e.g. δ-MoC0.75 and oxygen-free γ′-MoC0.75 is small enough to allow the synthesis of the latter phase in the absence of kinetic constraints. Annealing experiments of metastable δ-MoC1−x and γ′-MoC1−x films showed two different reaction products suggesting that kinetic effects play an important role in the decomposition of these phases.
Ämnesord
- NATURVETENSKAP -- Fysik (hsv//swe)
- NATURAL SCIENCES -- Physical Sciences (hsv//eng)
Nyckelord
- Molybdenum carbide
- Carbides
- Chemical vapor deposition
Publikations- och innehållstyp
- ref (ämneskategori)
- art (ämneskategori)
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