Noncontact scanning force microscopy based on a modified tuning fork sensor

Distance control using a tuning fork setup for the detection of shear force s is a standard configuration in scanning near-field optical microscopy (SN OM). Based on this concept, a modified sensor was developed, where a standa rd silicon tip for atomic force microscopy (AFM) is attached to the front e nd of one prong of a 100 kHz quartz tuning fork oscillator. Comparison of f orce curves of a standard tapping-mode AFM cantilever, a conventional fiber tip SNOM sensor and the novel AFM tip shear force sensor demonstrate an en hanced stability and sensitivity of the new sensor. Due to the rigid sensor design the force curves of the AFM tip shear force sensor indicate a perfe ct noncontact behavior under normal conditions in air. Noncontact images sh ow a comparable resolution to conventional force microscopy. (C) 2000 Ameri can Institute of Physics. [S0034- 6748(00)02708-8].