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

72 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
Externally publishedYes

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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