High-resolution synchrotron photoemission studies of the electronic structure and thermal stability of CH3- And C2H 5-functionalized Si(111) surfaces

Bengt Jaeckel, Ralf Hunger, Lauren J. Webb, Wolfram Jaegermann, Nathan S Lewis

Research output: Contribution to journalArticle

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Abstract

The relative coverage, thermal stability, and electronic properties of CH3- and C2H5-functionalized Si(111) surfaces prepared by a two-step chlorination/alkylation procedure have been compared using high-resolution synchrotron photoemission spectroscopy. Whereas the CH3-terminated Si(111) surface showed only one C 2s peak for the occupied σ orbitais, the C 2s spectra of C2H 5-terminated Si(111) surfaces showed a symmetric splitting of the occupied σ orbitals, as expected for an ethyl moiety bonded to the surface. The C2H5 termination resulted in an unpinning of the Si surface Fermi level, with a band bending of ∼0.2 eV, and produced a surface dipole potential step of -0.23(15) eV. The observed close-to-flat-band condition is similar to that of CH3-Si(111) and is consistent with H termination of the non-alkylated Si atop sites in the two-step chlorination/ alkylatipn process. The C2H5-functionalized Si(111) surfaces decomposed at temperatures >300°C, whereas CH 3-Si(111) surfaces were stable up to at least 440°C. The data clearly highlight the similarities and identify some significant differences between the behavior of the CH3- and C2H 5-functionalized Si(111) surfaces.

Original languageEnglish
Pages (from-to)18204-18213
Number of pages10
JournalJournal of Physical Chemistry C
Volume111
Issue number49
DOIs
Publication statusPublished - Dec 13 2007

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Photoemission
Synchrotrons
Electronic structure
synchrotrons
Thermodynamic stability
thermal stability
photoelectric emission
electronic structure
high resolution
chlorination
Chlorination
alkylation
Alkylation
Photoelectron spectroscopy
Fermi level
Electronic properties
Fermi surfaces
methylidyne
dipoles
orbitals

ASJC Scopus subject areas

  • Physical and Theoretical Chemistry
  • Electronic, Optical and Magnetic Materials
  • Surfaces, Coatings and Films
  • Energy(all)

Cite this

High-resolution synchrotron photoemission studies of the electronic structure and thermal stability of CH3- And C2H 5-functionalized Si(111) surfaces. / Jaeckel, Bengt; Hunger, Ralf; Webb, Lauren J.; Jaegermann, Wolfram; Lewis, Nathan S.

In: Journal of Physical Chemistry C, Vol. 111, No. 49, 13.12.2007, p. 18204-18213.

Research output: Contribution to journalArticle

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