Berlin 2008 – wissenschaftliches Programm
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O: Fachverband Oberflächenphysik
O 43: Poster Session II - MA 141/144 (Surface Spectroscopy on Kondo Systems; Frontiers of Surface Sensitive Electron Microscopy; Methods: Scanning Probe Techniques+Electronic Structure Theory+Other; Time-Resolved Spectroscopy of Surface Dynamics with EUV and XUV Radiation; joined by SYNF posters)
O 43.26: Poster
Dienstag, 26. Februar 2008, 18:30–19:30, Poster F
Use of a “needle-sensor” for non-contact scanning force microscopy and simultaneous measurement of the tunneling current — Bert Voigtländer1 and •Irek Morawski1,2 — 1Institute of Bio- and Nanosystems (IBN 3), and cni – Center of Nanoelectronic Systems for Information Technology, Research Centre Jülich, 52425 Jülich, Germany — 2Institute of Experimental Physics, University of Wrocław, pl. Maxa Borna 9, PL 50-204 Wrocław, Poland
A simultaneous measurement of forces and tunneling current during imaging of surfaces is of great interest. We present AFM/STM images of graphite and metal surface obtained by means of the quartz needle-sensor with an attached tungsten tip at ambient conditions. The needle sensor is an extensional mode quartz oscillator operating at a frequency of 1 MHz and one is similar to a tuning fork sensor more frequently used in scanning force microscopy. This sensor has been operated with a phase locked loop (PLL) control extended with an additional electronic circuit, namely an attenuator, two band-pass amplifier stages, providing both: sub-angstroms mechanical oscillation amplitude and high signal/noise ratio. Dependences of the frequency shift against a tip-surface displacement measured for mentioned surfaces are presented. A "feedback circuit enabled" method of a calibration of the needle-sensor vibration amplitude is proposed and discussed.