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 17.84: Poster

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

Dynamics of laser induced phase transitions of liquids at surfaces — •Sebastian Fischer, Florian Lang, Johannes Boneberg, and Paul Leiderer — Fachbereich Physik, Universität Konstanz, Fach M676, 78457 Konstanz

The phase-transition dynamics of isopropanol films with thicknesses on the order of 100 nm deposited on silicon wafers are investigated. A nanosecond laser pulse is used to heat the substrate. Due to heat transfer, the fluid adjacent to the interface evaporates and the film on top is ejected as an intact liquid layer. The phase transition and the ejection process are monitored by reflectometry with a temporal resolution of about 200 ps and a spatial sensitivity on the nanometre-scale in the direction perpendicular to the substrate.We demonstrate that this approach allows us to determine the generated pressures, the achievable superheating and the relevant timescales of the process and as a consequence provides insight into the nature of the very early stages of the phase transition.