Dresden 2011 – scientific programme
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O: Fachverband Oberflächenphysik
O 35: Poster Session I (Scanning probe methods)
O 35.19: Poster
Tuesday, March 15, 2011, 18:30–22:00, P3
Preparation and characterization of metal coated STM tips — •Sergej Burbach, Martin Wenderoth, Bernhand Spicher, and Rainer G. Ulbrich — IV. Physikalisches Institut, Georg-August Univ. Göttingen, Germany
We present an in situ preparation technique to produce scanning tunnelling microscopy tips coated with different metals and with a high reproducibility. This approach allows to vary the workfunction of STM tips or to prepare probes suitable for spin polarized STM. Based on a movable UHV chamber working at a base pressure of (1·10−10 mbar) the prepared tips can be transferred directly into the STM without breaking the vacuum.
As a starting point we use electrochemically etched tungsten tips with a radius of a few nanometer. After heating and sputtering the tips in UHV, thin metal films (e.g. Fe, Ag) are deposited using an electron beam evaporator. Monolayer thickness control is implemented using a quartz balance. To control the different steps of the tip preparation (heating, sputtering, deposition) the set-up allows in situ characterization using field emission. A quick switching between preparation and characterization is possible and leads to a high yield of atomically resolving tips. The different steps of the preparation have been controlled by ex situ scanning electron microscopy. This project is supported by SPP 1285.