Dresden 2009 – scientific programme

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O: Fachverband Oberflächenphysik

O 54: Nano-optics of metallic and semiconducting nanostructures (experiments II)

O 54.5: Talk

Thursday, March 26, 2009, 16:00–16:15, SCH A216

Optical characterisation of ripple formation through oblique incidence ion sputtering of Ag(001) — •Frank Everts, Herbert Wormeester, and Bene Poelsema — Solid State Physics, MESA+ Institute for Nanotechnology, University of Twente, Enschede, The Netherlands

Oblique incidence ion sputtering leads to the formation of ripple patterns on the surface of many materials. The temporal evolution of these ripple patterns can be measured in-situ with Reflection Anisotropy Spectroscopy (RAS). The periodicity of the ripple pattern supports the excitation of surface plasmons on a Ag(001) surface. This enables a rather straightforward interpretation of the measured optical spectrum. Ion sputtering at a polar angle of incidence with the normal of 70 deg. and beyond, provides a RAS spectrum that is characterized by a single peak, related to the periodicity between the ripples. Sputtering at a polar angle of incidence with the normal of 61 deg. also leads to an additional feature in the RAS spectrum that is attributed to an average periodicity of the ripple length, next to the peak that is related to the periodicity perpendicular to the ripples. The analysis of the optical spectra will be discussed in relation to the results of Low Energy Electron Diffraction (LEED) images obtained after sputtering.