Epitaxial chemical vapor deposition growth of single-layer graphene over cobalt film crystallized on sapphire

Hiroki Ago, Yoshito Ito, Noriaki Mizuta, Kazuma Yoshida, Baoshan Hu, Carlo M. Orofeo, Masaharu Tsuji, Ken Ichi Ikeda, Seigi Mizuno

    Research output: Contribution to journalArticle

    219 Citations (Scopus)

    Abstract

    Epitaxial chemical vapor deposition (CVD) growth of uniform single-layer graphene is demonstrated over Co film crystallized on c-plane sapphire. The single crystalline Co film is realized on the sapphire substrate by optimized high-temperature sputtering and successive H2 annealing. This crystalline Co film enables the formation of uniform single-layer graphene, while a polycrystalline Co film deposited on a SiO2/Si substrate gives a number of graphene flakes with various thicknesses. Moreover, an epitaxial relationship between the as-grown graphene and Co lattice is observed when synthesis occurs at 1000 °C; the direction of the hexagonal lattice of the single-layer graphene completely matches with that of the underneath Co/sapphire substrate. The orientation of graphene depends on the growth temperature and, at 900 °C, the graphene lattice is rotated at 22 ± 8° with respect to the Co lattice direction. Our work expands a possibility of synthesizing single-layer graphene over various metal catalysts. Moreover, our CVD growth gives a graphene film with predefined orientation, and thus can be applied to graphene engineering, such as cutting along a specific crystallographic direction, for future electronics applications.

    Original languageEnglish
    Pages (from-to)7407-7414
    Number of pages8
    JournalACS nano
    Volume4
    Issue number12
    DOIs
    Publication statusPublished - Dec 28 2010

    All Science Journal Classification (ASJC) codes

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

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