Dresden 2011 – wissenschaftliches Programm
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O: Fachverband Oberflächenphysik
O 35: Poster Session I (Scanning probe methods)
O 35.3: Poster
Dienstag, 15. März 2011, 18:30–22:00, P3
Developing a miniaturised device for in-situ STM tip cleaning using electron bombardment — •David Hellmann1, Ludwig Worbes1, and Achim Kittel2 — 1EHF, Fak. V, Physik, Carl von Ossietzky Universität Oldenburg — 2Experimental Polymer Physics, Faculty of Mathematics and Physics, University of Freiburg, 79104 Freiburg
Most SPM techniques rely on the assumption that both sample and tip are free from adsorbates and other residues. Getting a clean sample surface can be readily accomplished by applying ion sputtering, whereas finding an adequate treatment for tips is much more complicated. In principle one wants to desorb any molecules which might interfere with the anticipated measurement. This must be achieved without reducing the sharpness or the general geometry of the tip. Several devices are described in the literature which employ accelerated electrons to do this [1]. When such a procedure is applied in a variable temperature SPM, one has to keep the duration of any treatment as short as possible to avoid thermal drifts. To achieve this, we constructed an electron source which can be put into the sample holder while the tip stays in place. In our case, a tiny thermocouple is incorporated at the foremost tipapex, designed to perform measurements of the heat flow between a cooled or heated sample and the tip [2]. By means of these tips a direct measurement of the tip temperature during electron sputtering is possible. Literature: [1] S. Ernst et al., Science and Technology of Advanced Materials 8 (2007) [2] U. F. Wischnath, J. Welker, M. Munzel, A. Kittel, Review of Scientific Instruments 79 (2008)