Electromechanical Properties of Piezoelectric Thin Films by Optical Interferometry

Amanda Skrabut

Mentors: Ruyan Guo and Youwei Fu

 

            This research project focus on precision determination of electric field induced strain in a thin film sample due to piezoelectric effect.  When dimension change of a sample results in development of an electric field it is known as piezoelectric effect; or conversely an applied electric field to a sample resulting in a change in the sample dimension is known as converse piezoelectric effect.  It remains as a challenge to directly measure the displacement of a thin film sample as the displacement is typically in the order of sub nanometer for films of a few hundred-nanometer thick.  Optical interference technique that utilizes amplitude modulation and phase-lock will be used to measure the low level displacement.  Such measurements are important for electromechanical transduction and sensor applications.

            In this project, a single beam optical interferometer will be constructed to study Pb(Zr,Ti)O₃ (PZT) thin films.  It will then be of particular interest to compare the effects of the polycrystalline thin films with single crystal thin films.  The single crystal thin films have only been recently available by MBE technique.