High resolution noncontact atomic force microscopy imaging with oxygen-terminated copper tips at 78 K

Abstract

AFM experiments at 78 K with an atomically defined O-terminated Cu tip allow determining bond lengths of an organic molecule with high precision.

Protruding hydrogen atoms as markers for the molecular orientation of a metallocene

“…The experimental observation of the dumbbell shape suggests that the prerequisite of a stable tip during repulsive interactions with the hydrogen atoms can easily be fulfilled, even at room temperature. This is in line with previous findings of stable tips for submolecular resolution imaging at 77 K [37,38] and 300 K [39].…”

“…The experimental observation of the dumbbell shape suggests that the prerequisite of a stable tip during repulsive interactions with the hydrogen atoms can easily be fulfilled, even at room temperature. This is in line with previous findings of stable tips for sub-molecular resolution imaging at 77 K [ 37 – 38 ] and 300 K [ 39 ]. Due to the predominant repulsive interactions with the chemically rather inert hydrogen atoms, we speculate that the chemical identity of the tip is therefore of secondary importance.…”

Real-Space Identification of Non-Noble Single Atomic Catalytic Sites within Metal-Coordinated Supramolecular Networks

“…Closed β phase of dehydrogenated, flat melamine molecules on Cu(111) after annealing to 570 K. (a) STM image showing evenly distributed hollows (green circle) and bright point defects ( V = −1.0 V, I = 10 pA, Z max = 82 pm). (b,c) Constant-height nc-AFM data showing tunneling current and frequency shift images simultaneously recorded at 78 K . Two short-range order arrangements are marked by a green circle and a white parallelogram.…”

“…The nc-AFM experiments were in constant-height mode with an amplitude of 1.0 Å and, if not otherwise stated, at a temperature of ∼5 K. The observed main AFM signal is the frequency shift Δf compared to the free resonance frequency f 0 of the qPlus sensor. All AFM images are recorded with an atomically defined O-terminated copper tip, which was functionalized on a (2×1)­O-reconstructed Cu(110) surface by indentation of 1–8 Å. ,, The intactness of the functionalized tip after measuring the prepared sample is controlled by subsequent unambiguous contrast analysis on the (2×1)­O-reconstructed Cu(110) surface. , The shown SPM data is processed and filtered by the Scanning Probe Image Processor, SPIP5.1. Slightly Gaussian-filtered images are shown with absolute Δ f values in the color bar, whereas for Laplace of Gaussian-filtered images no quantitative values are given.…”

“…29,30,42 The intactness of the functionalized tip after measuring the prepared sample is controlled by subsequent unambiguous contrast analysis on the (2×1)O-reconstructed Cu(110) surface. 35,42 The shown SPM data is processed and filtered by the Scanning Probe Image Processor, SPIP5.1. Slightly Gaussian-filtered images are shown with absolute Δf values in the color bar, whereas for Laplace of Gaussian-filtered images no quantitative values are given.…”