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O: Fachverband Oberflächenphysik

O 49: Oxide and Insulator Interfaces I

O 49.2: Talk

Wednesday, March 20, 2024, 10:45–11:00, MA 144

Metal-oxide surfaces: Chemical selective nc-AFM imaging with O-terminated copper tips — •Philipp Wiesener¹, Johanna Hütner², Jan Balajka², Bertram Schulze Lammers¹, Harald Fuchs¹, Saeed Amirjalayer¹, and Harry Mönig¹ — ¹Physikalisches Institut, Universität Münster, Germany — ²Institute of Applied Physics, TU Wien, Austria

Previously we investigated the performance of various atomically defined tip terminations on the Cu(110)O(2x1) surface with non-contact AFM [1]. A direct comparison of the imaging properties shows, that only for an oxygen terminated copper tip (CuOx-tip [2]) a chemical selective contrast between metal and oxygen atoms on the surface can be observed.

In this work we exhibit the generalized ability of CuOx-tips for an outstanding characterization of metal-oxide surfaces. By performing constant height measurements on a variety of copper-, iron-, titanium- and aluminum-oxide systems with increasing structural complexity the robustness of the chemical selectivity is demonstrated. For an additional contrast analysis we complement our site-selective microscopy with force spectroscopy measuerements on the observerd metal and oxygen atoms and investigate predominant defects.

Supporting DFT calulations reveal that the chemical selectivity can be explained by purely electrostatic interactions, which are determined by the strongly electronegative tip termination.

[1] B. Schulze Lammers et. al., Nanoscale 13, 13617 (2021).

[2] H. Mönig et al., ACS Nano 10, 1201-1209 (2015).

Keywords: nc-AFM; metal-oxide surfaces; chemical selective imaging; copper-oxide tip (CuOx-tip)