Regensburg 2019 – wissenschaftliches Programm
O 47.3: Poster
Dienstag, 2. April 2019, 18:00–20:00, Poster D
High resolution imaging of organic molecules using Q-controlled amplitude modulation atomic force microscopy with CO-functionalized tips — •Daniel Martin-Jimenez1, Alexander Ihle1, Sebastian Ahles2, Hermann A. Wegner2, Andre Schirmeisen1, and Daniel Ebeling1 — 1Institute of Applied Physics (IAP), Justus Liebig University Giessen, Heinrich-Buff-Ring 16, 35392 Giessen, Germany — 2Institute of Organic Chemistry, Justus Liebig University Giessen, Heinrich-Buff-Ring 17, 35392 Giessen, Germany
The so-called bond imaging atomic force microscopy (AFM) technique has become an invaluable tool for studying organic molecules on surfaces. The key feature of this technique is to functionalize the AFM-tip with a single molecule, e.g., CO. Hereby, the imaging capabilities of dynamic mode AFM are improved, which allows to determine the precise orientation and internal structure of adsorbed organic molecules. Usually, these measurements are performed by operating tuning fork sensors in frequency modulation mode at low temperatures in ultrahigh vacuum conditions. The high quality factors of the tuning fork sensors under these conditions typically prohibit operation in amplitude modulation mode due to the slow response time caused by the low damping environment. Here, we use the Q-control technique to reduce the effective quality factor of the sensor from about 30000 to 3000. This enables submolecular amplitude modulation imaging with a lateral resolution and signal to noise performance comparable to frequency modulation mode.