Regensburg 2013 – wissenschaftliches Programm

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O: Fachverband Oberflächenphysik

O 58: Poster Session III (Solid-liquid interfaces; Scanning probe and other methods; Electronic structure theory; Spin-orbit interaction)

O 58.55: Poster

Mittwoch, 13. März 2013, 18:15–21:45, Poster B1

Highly controlled electron bombardment of SPM-tips for cleaning — David Hellmann, Ludwig Worbes, Konstantin Kloppstech, Nils Könne, and •Achim Kittel — EHF, Faculty V, Department of Physics, C. v. O. University of Oldenburg, 26129 Oldenburg, Germany

In the field of scanning probe microscopy, it is of great importance to operate with a well defined state of sample and probe with respect to unintentionally adsorbed molecules. There are many techniques for tip cleaning described in literature; among others the use of accelerated electrons as an energy source is reported. So far, all of the setups described, yielded either no or only indirect information about the probe’s temperature reached during the cleaning procedure, which is an important quantity to control the process. The Near-Field Scanning Thermal Microscopy probe not only serves as scanning tunneling microscope tip, but also includes a thermosensor in the vicinity of the probe’s apex. These sensors are very delicate because they combine different kind of materials. We use electron bombardment for cleaning these unique sensors, while the thermosensor is used as a sensor in the loop which is controlling the procedure. We observed probe temperatures up to 1800 K for a few tens of milliseconds without causing any damage to the tip function. We describe here the device as well as experimental data concerning the relation between the energies used for cleaning and the resulting temperature of the probe. The presented data might serve as an indicator for other setups where a direct measurement of the temperature of the apex is impossible.