Berlin 2008 – scientific programme

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O: Fachverband Oberflächenphysik

O 94: Methods: Other Experimental Techniques II

O 94.2: Talk

Friday, February 29, 2008, 12:15–12:30, MA 141

Scanning of the near-field thermal heat transfer — •Robert Berganski, Uli Wischnath, and Achim Kittel — Energy and Semiconductor Research Laboratory - University of Oldenburg

The heat transfer is measured by means of a scanning near-field thermal microscope based on a commercial scanning tunnelling microscope (STM). Hereby a miniaturized coaxial thermocouple is kept at a constant distance above the surface by using the constant current mode of the STM while the change of the temperature at the tip is recorded. Thereby the heat transfer and the sample topography are measured at the same time and, thus, the heat transfer can be correlated to the surface morphology. The investigated heat transfer relies on evanescent modes of the thermal transfer between the tip at room temperature and the sample at about 110K. All other interfering heat transfer mechanisms are excluded by using ultra high vacuum conditions. In the present contribution the focus lies on the material dependence of these evanescent modes which are reaching a few nano-meter into the vacuum. By varying the material of the sample surface the influence of the dielectric properties of the material and the morphology of the surface are studied.