Regensburg 2007 – scientific programme
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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 17.24: Poster
Monday, March 26, 2007, 17:30–20:30, Poster C
Modification of a HOPG and DLC/Si surface after radiation with the Free elektron LAser in Hamburg (FLASH) — •Björn Siemer1, Carsten Thewes1, Tim Hoger1, Marco Rutkowski1, Helmut Zacharias1, Rolf Treusch2, and Stefan Düsterer2 — 1Physikalisches Institut, Westfälische Wilhelms-Universität Münster, 48149 Münster — 2HASYLAB, DESY, 22603 Hamburg
The new free electron laser (FEL) at FLASH combines high photon energy with high pulse energy. A diamond like carbon (DLC) and HOPG surface were illuminated with photon energies of 58 eV and 38 eV. The pulse energy averaged around 30 µ J/pulse and the intensity around 1012 W/cm2. DLC is commonly used for the construction of XUV mirrors. We use HOPG for chemical reactions on surfaces activated by XUV radiation. The action of these light pulses on DLC/Si and graphite under focussed radiation of 58 eV for DLC/Si and 38 eV for HOPG is analysed. A change in reflectivity is visible under a light microscope. But an AFM profile and measurements with a profilometer yield no topology changes for both surfaces. We further present recent results of STM measurements of the modified surface.