[18p-Z16-1~16] 9.1 Dielectrics, ferroelectrics

▲ [18p-Z16-15] Evaluation of lead-free KNbO₃ piezoelectric thin films for environmental and biosensor applications

〇(M2C)PhyuPhyu Khin Sin^1,2, May Phyo Paing^1,2, Thithi Lay¹ (1.Dept. of Chem. Josai University. JP, 2.Dept. of Phys. University of Yangon MM)

Keywords:KNbO_3 thin film, Electromechanical properties, Hydrothermal method

Recently, the development of lead-free piezoelectric materials for environmental and biosensor applications is in focus to replace PZT because of their lead content and production of hazardous lead oxide during fabrication process. In this research, a biocompatible lead-free piezoelectric KNbO₃ film was grown on LiTaO₃ single crystal by hydrothermal method and evaluates its electromechanical properties and piezoelectric properties. Linear two-dimensional finite element method (2D-FEM) was used prior to the experiment to estimate the values of electromechanical coupling coefficient (k_t) and mechanical quality factor (Q_m). KNbO₃ film has acquired electromechanical coupling coefficient k_t 0.37 calculated from response of impedance with frequency as shown in figure 1 and simulation result of k_t was approximately 0.4. It also exhibits 22.4kV/cm coercive electric field and 8μC/cm² remnant polarization without poling treatment and shows P-E hysteresis characteristics as in figure 2. Experiment and simulation results are comparable with PZT ceramic sensor values which are currently used in environmental and biosensor applications.