Vibrational properties and charge transfer of adsorbed on Si(111) and Si(100) surfaces

Shozo Suto, Kazuyuki Sakamoto, Takanori Wakita, Chang Wu Hu, Atsuo Kasuya

Research output: Contribution to journalArticlepeer-review

62 Citations (Scopus)


We report here the measurements of vibrational excitation spectra and the temperature dependence of (Formula presented) molecules adsorbed on Si(111)-(Formula presented) and Si(100)-(Formula presented) surfaces using high-resolution electron-energy-loss spectroscopy in combination with scanning tunneling microscopy. A quantitative determination of the molecular charge state is obtained by the lower energy shifts of vibrational modes of (Formula presented) upon adsorption. On the Si(111)-(Formula presented) surface, the amount of charge transfer from the surface to a (Formula presented) molecule is estimated to be (Formula presented) electrons at the coverage lower than 0.25 monolayer (ML) and (Formula presented) electrons as an average at 1 ML. On the contrary, no indication of charge transfer is observed on the Si(100)-(Formula presented) surface at a coverage lower than 1 ML. The difference in the charge state on both surfaces is attributed to the difference in the nature of surface states. After annealing 1 ML (Formula presented) film at 500 K, the strong interaction between the surface Si atom and a (Formula presented) molecule is indicated by the softening of vibrational modes on both surfaces.

Original languageEnglish
Pages (from-to)7439-7445
Number of pages7
JournalPhysical Review B - Condensed Matter and Materials Physics
Issue number12
Publication statusPublished - Jan 1 1997
Externally publishedYes

ASJC Scopus subject areas

  • Electronic, Optical and Magnetic Materials
  • Condensed Matter Physics


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