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O: Fachverband Oberflächenphysik

O 35: Poster Session II (Polymeric biomolecular films; Nanostructures; Electronic structure; Spin-orbit interaction; Phase transitions; Surface chemical reactions; Heterogeneous catalysis; Particles and clusters; Surface magnetism; Electron and spin dynamics; Surface dynamics; Methods; Electronic structure theory; Functional molecules)

O 35.39: Poster

Dienstag, 27. März 2012, 18:15–21:45, Poster B

Photo-induced tunneling current microscope setup for UHV applications — •Uwe Schmitt, Andreas Englisch, and Uwe Hartmann — Institute of Experimental Physics, Universität des Saarlandes, P.O. Box 15 11 50, D-66041 Saarbrücken

In order to measure photo-induced tunneling currents on clean metal and semiconductor surfaces an UHV-STM-system was completed with suitable optical components which allows a simultaneous illumination of the sample with two wavelengths. The wavelengths can be modulated in the intensity with different modulation frequencies in order to detect the influence of both wavelengths with a lock-in-amplifier. The modulation deep can be chosen in a way that the DC-part of the light intensity determines the time independent photo conductivity and consequently the tunnel gap which is controlled by the feed-back-loop. In the original UHV-system (Omicron VT-STM) the Scala-electronic was replaced by a low cost controller from Soft dB.