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Title: Electrophilic surface sites as precondition for the chemisorption of pyrrole on GaAs(001) surfaces

We report how the presence of electrophilic surface sites influences the adsorption mechanism of pyrrole on GaAs(001) surfaces. For this purpose, we have investigated the adsorption behavior of pyrrole on different GaAs(001) reconstructions with different stoichiometries and thus different surface chemistries. The interfaces were characterized by x-ray photoelectron spectroscopy, scanning tunneling microscopy, and by reflectance anisotropy spectroscopy in a spectral range between 1.5 and 5 eV. On the As-rich c(4 × 4) reconstruction that exhibits only nucleophilic surface sites, pyrrole was found to physisorb on the surface without any significant modification of the structural and electronic properties of the surface. On the Ga-rich GaAs(001)-(4 × 2)/(6 × 6) reconstructions which exhibit nucleophilic as well as electrophilic surface sites, pyrrole was found to form stable covalent bonds mainly to the electrophilic (charge deficient) Ga atoms of the surface. These results clearly demonstrate that the existence of electrophilic surface sites is a crucial precondition for the chemisorption of pyrrole on GaAs(001) surfaces.
Authors:
 [1] ;  [2] ;  [3] ;  [1]
  1. Institut für Festkörperphysik, Technische Universität Berlin, Hardenbergstr.36, D-10623 Berlin (Germany)
  2. (Germany)
  3. Department of Electronics and Telecommunications, Norwegian University of Science and Technology, NO-7491 Trondheim (Norway)
Publication Date:
OSTI Identifier:
22415473
Resource Type:
Journal Article
Resource Relation:
Journal Name: Journal of Chemical Physics; Journal Volume: 142; Journal Issue: 10; Other Information: (c) 2015 AIP Publishing LLC; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
37 INORGANIC, ORGANIC, PHYSICAL AND ANALYTICAL CHEMISTRY; ADSORPTION; ANISOTROPY; ATOMS; CHEMICAL BONDS; CHEMISORPTION; CHEMISTRY; EV RANGE; GALLIUM ARSENIDES; INTERFACES; PYRROLES; SCANNING TUNNELING MICROSCOPY; SPECTRAL REFLECTANCE; STOICHIOMETRY; SURFACES; X-RAY PHOTOELECTRON SPECTROSCOPY