Piezoelectric Response in the Contact Deformation of Piezoelectric Materials

Abstract

Microand nanoelectromechanical systems (MEMS and NEMS) using lowdimensional piezoelectric structures (piezoelectric thin films, nanowires, and nanobelts) [1–10] have potential applications in many areas, including biosensors, actuators, and motion-controllers due to intrinsic electromechanical coupling. The electromechanical coupling provides a unique route for sensing mechanical stimuli from the change in electric potential/field, and for controlling structural deformation via electrical loading [11], which determines the performance and lifetime of microand nanodevices during the device operation. It becomes of primary interest to experimentally and theoretically investigate the piezoelectric behavior of materials on both the microand nanoscales under electrical and mechanical loading for the development, design, and process control of MEMS and NEMS devices. Piezoelectricity is an interaction between mechanical deformation and electric field. Several techniques have been used to characterize the piezoelectric behavior of piezoelectric structures and materials, which are based on either the direct piezoelectric effect or the inverse piezoelectric effect. The direct piezoelectric effect is that mechanical deformation produces electric polarization, and the inverse piezoelectric effect represents electric field-induced mechanical strain [12]. The techniques using the direct piezoelectric effect include stress-induced charge (Berlincourt method) and indentation, and the techniques using the inverse piezoelectric effect consist of laser interferometers, laser scanning vibrometers, and piezoresponse force microscope. The Berlincourt method, the laser interferometers, and the laser scanning vibrometers can be readily used in determining the piezoelectric behavior of bulk piezoelectric materials, while it is very difficult if not impossible to apply these