Regensburg 2010 – scientific programme
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DS: Fachverband Dünne Schichten
DS 38: Layer Properties: Electrical, Optical and Mechanical Properties
DS 38.1: Talk
Thursday, March 25, 2010, 14:00–14:15, H8
Modification of coherent acoustic phonon lifetimes in thin gold films by self-assembled monolayers — •Mike Hettich1, Axel Bruchhausen1, Oliver Ristow1, Daniel Issenmann1, Tobias Geldhauser1, Ingo Wenke2, Jürg Bryner2, Jürg Dual2, and Thomas Dekorsy1 — 1Department of Physics and Center of Applied Photonics, Universität Konstanz, Germany. — 2Institute for Mechanical Systems, ETH Zürich, Switzerland.
The damping of coherent acoustic phonons in thin gold films has been investigated by asynchronous optical sampling (ASOPS)[1].
In order to measure the damping constants for various frequencies gold films are grown in a wedge shape. Different film thicknesses correspond to changes in the phonon oscillation frequencies which can therefore be measured by scanning over the sample surface.
For lower frequency phonons in the range of 50 GHz to ∼ 75 GHz a significant change in damping times is observed when a self assembled monolayer is added between the gold film and the substrate. The damping behaviour with and without self-assembled monolayer has been modelled with good agreement by a visco-elastic simulation.
[1] A. Bartels et al., Rev. Sci. Instr. 78, 035107 (2007).