Berlin 2005 – scientific programme

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O: Oberflächenphysik

O 46: Adsorption an Oberfl
ächen V

O 46.4: Talk

Tuesday, March 8, 2005, 16:30–16:45, TU EB420

Towards ultimate resolution in surface stress measurements — •Peter Kury and Michael Horn-von Hoegen — Institut für Laser- und Plasmaphysik, Universität Duisburg-Essen, 45141 Essen

Surface stress is one of the most important physical quantities for the evolution of structure and morphology on the surfaces of solids due to its large contribution to the total energy. Unfortunately, the direct measurement of surface stress is not possible, but it can be determined via the elastic response of a thin substrate as utilized in bending sample techniques like surface stress induced optical deflection (SSIOD) [1]. A sensitivity in the order of 1N/m, corresponding for example to a biaxially by 4.2% compressed germanium film of one monolayer thickness, can be easily achieved if proper mechanical isolation of the system and vibration damping are implemented. To reach an instrumental resolution in the order of 0.01N/m, however, it is necessary also to consider effects which are far from obvious in this context. Here we present modifications of SSIOD that allow the determination of surface stress with a resolution of 0.005N/m [2] corresponding to a sensitivity of less than 1% of a monolayer in typical adsorbate systems. Experimental results are shown for Sb/Si(001), Cs/Si(001) and Si/Si(111).
[1]: A. Schell-Sorokin et al., Phys. Rev. Lett. 64(9), 1039 (1990)
[2]: P. Kury et al., Rev. Sci. Instrum., in press (2004)