Origin of flat morphology and high crystallinity of ultrathin bismuth films

S. Yaginuma, T. Nagao, J. T. Sadowski, M. Saito, K. Nagaoka, Y. Fujikawa, T. Sakurai, T. Nakayama

    Research output: Contribution to journalArticlepeer-review

    62 Citations (Scopus)

    Abstract

    We have investigated the origin of "atomically flat" and "single-crystalline" growth of Bi films on Si(1 1 1)-7 × 7 through comparative experiments using Si(1 1 1)-β-√3 × √3-Bi as a control system. On the Si(1 1 1)-7 × 7 substrate, the majority of initial nuclei stabilize with pseudocubic (PC) paired layers analogous to the black phosphorus (BP) structure, and grow in a strong two-dimensional fashion that results in a "textured" but "atomically flat" surface morphology. After the coalescence of the BP-like grains at a nominal thickness of 4 monolayers (ML), a tiny number of minority hexagonal (HEX) bulk crystal nuclei, aligned commensurately with the substrate 7 × 7 lattice, cause the "textured" BP-like PC film to transform into a "single-crystalline" bulk-like HEX film. On the Si(1 1 1)-β-√3 × √3-Bi substrate, however, the BP-like structure breaks up into a conventional bulk-like PC structure and the HEX nucleation is suppressed up to as thick as ∼6 ML. Therefore, the morphology and crystallinity of the films are simply rough and polycrystalline, respectively.

    Original languageEnglish
    Pages (from-to)3593-3600
    Number of pages8
    JournalSurface Science
    Volume601
    Issue number17
    DOIs
    Publication statusPublished - 2007 Sep 1

    Keywords

    • Bismuth
    • Electron diffraction
    • Growth
    • Nucleation
    • Scanning tunneling microscopy
    • Structural transformation

    ASJC Scopus subject areas

    • Condensed Matter Physics
    • Surfaces and Interfaces
    • Surfaces, Coatings and Films
    • Materials Chemistry

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