TY - JOUR
T1 - Origin of flat morphology and high crystallinity of ultrathin bismuth films
AU - Yaginuma, S.
AU - Nagao, T.
AU - Sadowski, J. T.
AU - Saito, M.
AU - Nagaoka, K.
AU - Fujikawa, Y.
AU - Sakurai, T.
AU - Nakayama, T.
N1 - Funding Information:
The authors are grateful to Dr. B. Tsuchiya, and Professors J. Yuhara, S. Nagata, and T. Shikama for RBS measurements, and M. Maekawa for helpful discussions. This work has been partly supported by Grants-in-Aid for Scientific Research from the Ministry of Education, Culture, Sports, Science, and Technology of Japan. STM topographic images were processed using WSxM software [23] .
PY - 2007/9/1
Y1 - 2007/9/1
N2 - 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.
AB - 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.
KW - Bismuth
KW - Electron diffraction
KW - Growth
KW - Nucleation
KW - Scanning tunneling microscopy
KW - Structural transformation
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U2 - 10.1016/j.susc.2007.06.075
DO - 10.1016/j.susc.2007.06.075
M3 - Article
AN - SCOPUS:34548026228
VL - 601
SP - 3593
EP - 3600
JO - Surface Science
JF - Surface Science
SN - 0039-6028
IS - 17
ER -