Rectification of force-distance curve using capacitance measurement

We demonstrate the rectification of force spectroscopy in noncontact atomic force microscopy. The resonant frequency shift $(Δf)$ in the probe oscillation and distance-modulated capacitance $(dC/dZ)$ are simultaneously measured on thin dielectric films as a function of externally applied bias voltage and tip-sample distance $Z$⁠. Analysis of $dC/dZ$ spectroscopy has revealed that the probe-tip position shifts due to the attractive force acting between the tip and a sample. We show that the shifted $Δf-Z$ curve can be rectified and the deformation of the probe tip can be quantitatively assessed.