Dresden 2009 – wissenschaftliches Programm
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O: Fachverband Oberflächenphysik
O 42: Poster Session II (Nanostructures at surfaces: arrays; Nanostructures at surfaces: Dots, particles, clusters; Nanostructures at surfaces: Other; Nanostructures at surfaces: Wires, tubes; Metal substrates: Adsorption of O and/or H; Metal substrates: Clean surfaces; Metal substrates: Adsorption of organic/bio moledules; Metal substrates: Solid-liquid interfaces; Metal substrates: Adsorption of inorganic molecules; Metal substrates: Epitaxy and growth; Heterogeneous catalysis; Surface chemical reactions; Ab-initio approaches to excitations in condensed matter; Organic, polymeric, biomolecular films– also with adsorbates; Particles and clusters)
O 42.23: Poster
Mittwoch, 25. März 2009, 17:45–20:30, P2
Laser-induced mechanical excitation of nanostructures (and their measurement by means of SXM) — •Markus Schmotz1, Tobias Geldhauser1, Patrick Bookjans2, and Paul Leiderer1 — 1Universität Konstanz, Deutschland — 2James Madison University, USA
Information about deformations of nanostructures in the Gigahertz regime is rather sparse until now. Especially irradiation with short laser pulses is hardly studied. Our work aims at creating Surface Acoustic Waves (SAW) in the Gigahertz range based on short laser pulse techniques and using them to excite nanostructures. Generation and optically based detection of SAWs by single shot experiments showed first results. A new approach to the GHz regime is to utilize raster-probe techniques. Therefore we are developing a new detection method based on a homebuilt, variable temperature Scanning Tunnelling Microscope (STM). Exploiting the highly non-linear I(z)-characteristic of the tunnelling-gap allows us to determine elongation in the sub-Å regime with high lateral resolution. Since the STM lacks a suitable temporal resolution for GHz-waves, we started to investigate vibrational modes in thin, free standing silicon membranes (thickness some hundred nm) in the kHz to MHz regime. In this range our STM electronics are fast enough to resolve the vibrations almost one-to-one. Comparison between optically gained information and corresponding STM data show excellent agreement. Measurements with the STM and according optical techniques at frequencies up to the GHz regime are currently under investigation.