Atomic-Resolution Imaging of Graphite–Water Interface by Frequency Modulation Atomic Force Microscopy

Abstract

Atomic-resolution images of a graphite (0001) surface in water were successfully obtained by frequency modulation atomic force microscopy. Atomic scale features with a periodicity of 0.25 nm were resolved with an interaction force of less than 100 pN using a stiff cantilever and a very small oscillation amplitude of 0.11 nm (0.21 nm peak-to-peak). Furthermore, structured-water layers on a hydrophobic graphite surface were visualized by two-dimensional frequency shift mapping. The results were compared with a molecular-scale hydration structure at an interface between a hydrophilic mica surface and water.