Dynamic nanoimpedance characterization of the atomic force microscope tip-surface contact.

Nanoimpedance measurements, using the dynamic impedance spectroscopy technique, were carried out during loading and unloading force of a probe on three kinds of materials of different resistivity. These materials were: gold, boron-doped diamond, and AISI 304 stainless steel. Changes of impedance spectra versus applied force were registered and differences in the tip-to-sample contact character on each material were revealed. To enable comparison between materials and phases, a new standardization method is proposed, which simulates conditions of initial contact.