Regensburg 2007 – wissenschaftliches Programm

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O: Fachverband Oberflächenphysik

O 17: Poster Session I (Nanostructures at Surfaces; Metal Substrates: Epitaxy and Growth; Methods: Scanning Probe Techniques; Phase Transitions)

O 17.70: Poster

Montag, 26. März 2007, 17:30–20:30, Poster C

Ablation dynamics of solid carbon dioxide after ns laser illumination — •Johannes Graf, Laura Hennemann, Johannes Boneberg, and Paul Leiderer — Fachbereich Physik, Universität Konstanz, Fach M676, 78457 Konstanz

In recent publications we already introduced a new laser based cleaning technique called Matrix Laser Cleaning. In this technique a matrix of an cryogenic solid , e.g. carbon dioxide, is condensed onto the substrate prior to the laser pulse. After ns laser irradiation the subsequent vaporization of the matrix molecules constitutes the dominant cleaning mechanism. By a careful adjustment of the process parameters cleaning down to at least 50 nm sized particles can be achieved with an efficiency close to 100%. In contrast to Steam Laser Cleaning this technique does not face wetting problems or the formation of watermarks.

In this presentation we want to focus on first experiments on the underlying mechanism, the ablation of the cryogenic matrix. Therefore we built a reflectometry and scattering light setup with sub-ns time resolution to investigate the ablation dynamics with a vertical resolution of a few nanometers. By careful analysis of these signals conclusions on the underlying mechanisms can be drawn. The results of ns- and fs-illumination will be compared.