Development of a piezoelectric self-excitation and self-detection mechanism in PZT microcantilevers for dynamic scanning force microscopy in liquid

We report on the first successful operation of a cyclic contact scanning force microscope (SFM) using a self-excited cantilever in liquid. Based on a new structure including a PZT reference pattern and a free-standing PZT cantilever, the piezoelectric self-excitation and self-detection mechanism for a PZT microcantilever was developed successfully. The topography is recorded by measuring the piezoelectric current variation, which corresponds to the vibration. Since the acoustic excitation from the external oscillator no longer exits, a clear single resonance peak can be obtained by using this self-excited force sensing PZT cantilever. Clear grating imaging in liquid was demonstrated, and it is compatible with the image taken in air. The future potential of applying this piezoelectric SFM to the characterization of biological samples in liquid is very promising.