Regensburg 2010 – wissenschaftliches Programm

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O: Fachverband Oberflächenphysik

O 60: Poster Session III (Methods: Atomic and electronic structure; Methods: electronic structure theory; Methods: Molecular simulations and statistical mechanics; Methods: Sanning probe techniques; Methods: other (experimental); Methods: other (theory) )

O 60.18: Poster

Mittwoch, 24. März 2010, 17:45–20:30, Poster B2

SPM tip cleaning by electron-bombardment for investigation of samples prepared by applying nanospherelithography (NSL) — •David Hellmann, Uli F. Wischnath, and Achim Kittel — EHF, Fak. V, Physik, Carl von Ossietzky Universität Oldenburg

The heat transfer between a sample and a probe can be measured using a Near-field Scanning Thermal Microscope (NSThM) [1,2]. The NSThM combines a STM tip with a thermocouple sensor. Thus data concerning the heat transfer a few nm above the scanned surface can be collected by measuring the thermovoltage. Cleanliness of the tip and the sample is an issue of great importance as the NSThM seems to be more sensitive to adsorbates than traditional STM techniques. By applying nanospherelithography (NSL), structured surfaces have been prepared and subsequently scanned using a NSThM tip. Residues of unknown origin seem to persist on either the tip or the sample though intensive cleaning procedures have been applied to the latter. X-Ray-Photoelectron-Spectroscopy (XPS) conducted on the sample did not reveal the presence of residues. Therefore electron-bombardment has been applied to the tip, as this has been reported in [3] to be an established method to heat a tip to several hundred degrees Celsius. As the tip used here gives a thermovoltage when its temperature is changed, it should be possible to measure the heating effect of the bombardment directly. Interestingly, no clear evidence could be gathered that the tip can be heated up significantly. Literature: [1] A. Kittel et al., PRL 95, 224301 (2005) [2] U. Wischnath, RSI 79, 073708 2008 [3] S. Ernst et al., Science and Technology of Advanced Materials 8 (2007)