Regensburg 2019 – wissenschaftliches Programm
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O: Fachverband Oberflächenphysik
O 72: Poster Wednesday: Scanning Probe Techniques
O 72.8: Poster
Mittwoch, 3. April 2019, 17:45–20:00, Poster B2
Contrast mechanism in Scanning Field Emission Microscopy — •Gabriele Bertolini1, Robin Pröbsting1, Hugo Cabrera1, Urs Ramsperger1, Danilo Pescia1, and Oguzhan Gürlü1,2 — 1Laboratory for Solid State Physics, ETH Zurich, 8093 Zurich, Switzerland — 2Istanbul Technical University, Department of Physics, 34469 Istanbul, Turkey
We perform Scanning Tunneling Microscopy in the field emission regime by retracting the tip few nanometers away from the sample, out of the tunneling condition. By applying a higher negative potential to the tip with respect to the sample, field emission of electrons is achieved. Formally this technique is named as Scanning Field Emission Microscopy (SFEM) and it is based on STM in combination with Topografiner technology. SFEM can provide chemical and magnetic information of surfaces with nanometer level spatial resolution due to the high sharpness of the tip. During experiments we simultaneously measure the amount of emitted electrons from the tip, the absorbed electrons by the sample, as well as the electrons escaping the tip-sample junction. In our setup we also have an electron energy analyzer. In this work we present our results on the chemical contrast observed in different metal and semiconductor surfaces as well as metal/semiconductor interfaces using SFEM. We show how the contrast mechanism observed on the current and electron maps of the surface can be interpreted and can be enhanced.