Extraction of Electromechanical Coefficients from Capacitance–Voltage Measurements of Unannealed Solution‐Processed KNN Thin Films: Effects of Frequency and Electrostatic and Mechanical Deformation

Abstract

A solution‐processed piezoceramic thin‐film MπM parallel‐plate capacitor structure to determine electromechanical coefficient using capacitance–voltage measurements is demonstrated. Electrical loading is applied to the capacitor to stimulate out‐of‐plane longitudinal and transverse elongation. The piezoelectric coefficient (d 33) is estimated using the spatial deviation of thin‐film dimensions as a function of the applied electric field. The results are validated using finite element method‐based modeling and compared with several measurements in literature, including piezoresponse force microscopy‐based measurements, which are generally considered unreliable due to strong electrostatic interactions between the tip‐cantilever, and the charged sample surface, wherein such artifacts result in the overestimation of the electromechanical response of the material under investigation.