Three-dimensional atomic force microscopy mapping at the solid-liquid interface with fast and flexible data acquisition.

Hagen Söngen,Martin Nalbach,Angelika Kühnle,Holger Adam

doi:10.1063/1.4952954

Abstract

We present the implementation of a three-dimensional mapping routine for probing solid-liquid interfaces using frequency modulation atomic force microscopy. Our implementation enables fast and flexible data acquisition of up to 20 channels simultaneously. The acquired data can be directly synchronized with commercial atomic force microscope controllers, making our routine easily extendable for related techniques that require additional data channels, e.g., Kelvin probe force microscopy. Moreover, the closest approach of the tip to the sample is limited by a user-defined threshold, providing the possibility to prevent potential damage to the tip. The performance of our setup is demonstrated by visualizing the hydration structure above the calcite (10.4) surface in water.

Highlights

Dynamic atomic force microscopy (AFM) is a most valuable tool for studying solid-liquid interfaces in real space
We present the implementation of a three-dimensional mapping routine for probing solid-liquid interfaces using frequency modulation atomic force microscopy
The introduction of three-dimensional (3D)-AFM by Fukuma et al.9 has enabled the visualization of the interfacial hydration structure

Summary

INTRODUCTION

Dynamic atomic force microscopy (AFM) is a most valuable tool for studying solid-liquid interfaces in real space. One possibility is to use the distance feedback loop with low gain to adjust the average tipsample distance. This concept has been successfully applied in frequency modulation (FM)-AFM, bimodal AFM, and amplitude modulation AFM.. This concept has been successfully applied in frequency modulation (FM)-AFM, bimodal AFM, and amplitude modulation AFM.13 Another option, which is more suited to non-planar samples, is to stop the cantilever approach whenever a user-defined threshold is reached. This opens up the possibility to investigate, e.g., step edges, other non-planar structures and, allows to minimize potential damage to the tip. Kobayashi et al. employed a fieldprogrammable gate array in combination with a home-built AFM controller to perform threshold-based 3D mapping

IMPLEMENTATION

FM-AFM operation

Data acquisition and synchronization

PROOF OF CONCEPT

CONCLUSION