Regensburg 2010 – scientific programme
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O: Fachverband Oberflächenphysik
O 13: Semiconductor substrates: Adsorption
O 13.11: Talk
Monday, March 22, 2010, 17:30–17:45, H34
Self-assembly of aromatic heterocyclic molecules on GaAs surfaces — •Thomas Bruhn1,2, Bjørn Ove Fimland3, Michael Kneissl1, Norbert Esser1,2, and Patrick Vogt1 — 1TU Berlin, Institut für Festkörperphysik, Hardenbergstr. 36, 10623 Berlin, Germany — 2ISAS Berlin, Albert-Einstein-Str. 9, 12489 Berlin, Germany — 3NTNU, NO-7491 Trondheim, Norway
Although organic/inorganic interfaces are already used in a variety of technological applications, such as OLEDs or sensors, there is still no sufficient basic understanding of the structural and electronic parameters that influence the interface formation between the organic and the inorganic material. We investigate organic adsorbates on technologically important III-V surfaces. After having gained detailed understanding of the adsorption of unsaturated hydrocarbon ring molecules, we investigate the adsorption of the aromatic heterocyclic molecule Pyrrole (C4H4NH) on clean GaAs(001) surface reconstructions. The samples were prepared under UHV conditions and the adsorption process was monitored in-situ with reflectance anisotropy spectroscopy (RAS). The interfaces were characterized electronically by scanning tunneling microscopy (STM), scanning tunneling spectroscopy (STS) and photoemission spectroscopy (PES). The measurements show a significantly higher surface reactivity for the Ga rich surface reconstructions and indicate a physisorption of the adsorbed molecules at the As-rich c(4×4) reconstruction. Intra-molecular bondings could be identified in the tunneling spectra and molecular adsorption sites could be determined from the STM measurements.