Non-contact Friction Force Microscopy Exploiting Lateral Resonance Enhancement

A method for sensing the dissipation occurring when a sharp atomic force microscopy (AFM) tip is oscillated laterally above a surface at distances typical of non-contact mode AFM operation is established and demonstrated. Dissipation is detected by measuring the damping of lateral resonant modes of the AFM cantilever, excited independently after the lateral resonant mode identification, when the tip is approached to the surface in the AFM non-contact or tapping regime. Preliminary images on a gold/glass sample as well as force versus separation curves give a hint of the potential of the technique. This method may provide a means of achieving sensitivity on the nanometer scale to different materials, or to adsorbate presence, even on delicate surfaces not explorable by the more invasive contact-mode friction force microscopy.