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

Thomas Bruhn, Bjørn-Ove Fimland, Patrick Vogt
2015 Journal of Chemical Physics  
Originally published as: Bruhn, T., Fimland, B.-O., Vogt, P. (2015): 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
more » ... 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. C 2015 AIP Publishing LLC. [http://dx.
doi:10.1063/1.4906117 pmid:25770492 fatcat:3cjepuluzvcsdbv3ujflsw6d34