Intermittent contact interaction between an atomic force microscope cantilever and a nanowire

Abstract

We investigate in theory and experiment the intermittent contact interaction between an atomic force microscope (AFM) cantilever and a nanowire under ambient conditions. The nanowire is modeled as a spring reacting instantaneously to any change of the force between the wire and the cantilever. This implies that the cantilever is subject to an “effective” force-distance relation, containing not only the surface forces but also the deflection of the nanowire. Experimentally, CVD-grown tin oxide nanowires and lithographically structured silicon nanowire arrays were investigated by intermittent contact AFM. By comparison of experimental and simulated distance-dependent resonance curves it is found that the nanowires behave like “fast nanosprings” and that the adhesion force is one of the key factors determining distance-dependent resonance curves. The results are fully applicable to a scenario in which a cantilever equipped by a nanowire interacts with a surface.