Formation of ultrananocrystalline diamond/amorphous carbon composite films in vacuum using coaxial arc plasma gun

Kenji Hanada, Tomohiro Yoshida, You Nakagawa, Tsuyoshi Yoshitake

    Research output: Contribution to journalArticle

    29 Citations (Scopus)

    Abstract

    Ultrananocrystalline diamond (UNCD)/nonhydrogenated amorphous carbon (a-C) composite films were grown in vacuum using a coaxial arc plasma gun. From the X-ray diffraction measurement, the UNCD crystallite size was estimated to be 1.6 nm. This size is dramatically reduced from that (2.3 nm) of UNCD/hydrogenated amorphous carbon (a-C:H) composite films grown in a hydrogen atmosphere. The sp3/(sp3 + sp2) value, which was estimated from the X-ray photoemission spectrum, was also reduced to be 41%. A reason for it might be the reduction in the UNCD crystallite size. From the near-edge X-ray absorption fine-structure (NEXAFS) spectrum, it was found that the π*C=C and π*C≡C bonds are preferentially formed instead of the σ*C-H bonds in the UNCD/a-C:H films. Since the extremely small UNCD crystallites (1.6 nm) correspond to the nuclei of diamond, we consider that UNCD crystallite formation should be due predominantly to nucleation. The supersaturated condition required for nucleation is expected to be realized in the deposition using the coaxial arc plasma gun.

    Original languageEnglish
    Article number125503
    JournalJapanese journal of applied physics
    Volume49
    Issue number12
    DOIs
    Publication statusPublished - Dec 2010

    All Science Journal Classification (ASJC) codes

    • Engineering(all)
    • Physics and Astronomy(all)

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