Regensburg 2016 – wissenschaftliches Programm
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O: Fachverband Oberflächenphysik
O 39: 1D Metal Wires on Semiconductors II
O 39.2: Vortrag
Dienstag, 8. März 2016, 14:15–14:30, S052
Optical monitoring of Ag nanostructures on Si(557) — •Sandhya Chandola1, Eugen Speiser1, Jochen Räthel1, Ulrich Krieg2, Christoph Tegenkamp2, Herbert Pfnür2, and Norbert Esser1 — 1Leibniz-Institut für Analytische Wissenschaften - ISAS - e.V., Department Berlin, Schwarzschildstraße 8, 12489 Berlin, Germany — 2Leibniz Universität Hannover, Institut für Festkörperphysik, Appelstraße 2, 30167, Hannover, Germany
The optical response of the Si(557)-Ag surface has been studied with reflectance anisotropy spectroscopy (RAS) from 0.5 to 5 eV. Using the Si(557) surface as a template, various quasi-one dimensional (1D) Ag structures were grown and substantial differences between the structures were observed with RAS. At ∼ 0.3 ML of Ag, 1D chain structures were observed with STM and a large anisotropic response developed at 2.5 eV, related to the formation of Ag nanowires which are semiconducting. Further deposition up to 1.2 ML of Ag resulted in the formation of the (√3×√3) phase. The anisotropy at 2.5 eV disappeared and the overall optical response showed substantial modification. Small amounts of Ag, from 0.03 ML to 0.1 ML of Ag, were then deposited on the (√3×√3) surface to monitor the effects of doping on these structures. The RAS response showed a significant anisotropy towards the infrared for small amounts of doping. As RAS is only sensitive to the anisotropic optical response, which arises from stepped and facetted regions of the surface, it can be a sensitive tool to monitor the effects of excess Ag atoms concentrated at the step sites of the Si(557) surface which are supposed to be responsible for the doping mechanism.