Regensburg 2007 – wissenschaftliches Programm

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O: Fachverband Oberflächenphysik

O 44: Poster Session II (Semiconductors; Oxides and Insulators: Adsorption, Clean Surfaces, Epitaxy and Growth; Surface Chemical Reactions and Heterogeneous Catalysis; Surface or Interface Magnetism; Solid-Liquid Interfaces; Organic, Polymeric, Biomolecular Films; Particles and Clusters; Methods: Atomic and Electronic Structure; Time-resolved Spectroscopies)

O 44.80: Poster

Mittwoch, 28. März 2007, 17:00–19:30, Poster C

Using a scanning tunnelling microscope for pressure measurement — •Thomas Madena and Achim Kittel — Energy and Semiconductor Research Laboratory, Institute of Physics, University of Oldenburg

Changes in mechanical stress distorts the scanning tunnelling microscope (STM) operation during the scanning of the hight information. This effect is the starting point of the idea to use the STM-principle for pressure measurements. A simple tunnelling microscope without xy-scanning stage measures the bending of a membrane due to an applied pressure. The voltage applied to the hight control is now the dependent quantity of the pressure on the rear side of the membrane. The high resolution of the STM makes it possible to see displacement on the nanometer scale. The thickness and the choice of material of the membrane are free parameter to alter the steepness of the pressure sensor. Results of the measurements of the different sensor features are discussed, like the linearity of the characteristics and sensitivity of the sensor. A possible procedure to calibrate the sensor is proposed. Furthermore, the unwanted influence of different interfering quantities was investigated and solutions to reduce their influence are given. For example the influence of a temperature drift can be reduced by the right choice of the used materials.