Regensburg 2019 – wissenschaftliches Programm

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O: Fachverband Oberflächenphysik

O 10: New Methods and Developments II: Scanning Probe, Spectroscopic, and Diffraction Techniques

O 10.3: Vortrag

Montag, 1. April 2019, 15:30–15:45, H3

In-situ characterization of O-terminated copper tips for high-resolution atomic force microscopy — •Alexander Liebig and Franz. J. Giessibl — University of Regensburg, Regensburg, Germany

The use of chemically inert tips allows to directly probe the repulsive interaction regime and thus to obtain high spatial resolution. Gross et al. found in 2009 [1] that CO-terminated metal tips enable intramolecular resolution imaging of organic molecules. Later, it was found that terminating the tip apex with noble gas atoms [2] achieves a similar spatial resolution. Recently, Mönig et al. [3] proposed to use oxygen-terminated Cu tips that apparently are also quite inert, but are stiffer in lateral directions than CO tips. So far, to verify tip functionalization with oxygen, the STM and AFM contrast of copper oxide domains has been compared to calculated images for different tip models. Here, we apply the COFI method [4] and force spectroscopy to characterize O-terminated Cu tips in-situ on a Cu(110) surface. Our approach is an efficient way to experimentally determine both the structural composition as well as the chemical species of the tip apex. Knowledge of these properties is of crucial importance, especially if the tips are used for experiments on other sample systems. The experimental data about the tip structure and composition is expected to improve the precision of theoretical studies about the interaction between tip and sample. [1] L. Gross et al., Science 325, 1110 (2009). [2] F. Mohn et al., Appl. Phys. Lett. 102, 073109 (2013). [3] H. Mönig et al., ACS Nano 10, 1201 (2016). [4] J. Welker et al., Science 336, 6080 (2012).