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▲ [18p-Z16-14] Characterization of KNbO3 Piezoelectric Thin Films by Hydrothermal Method
Keywords:Lead free piezoelectric thin film, potassium niobate film, Hydrothermal method
Piezoelectric thin films with perovskite structure are in focus as lead- free piezoelectric material to reduce the environmental damage and hazard. In this research, KNbO3 films were synthesized on single crystal LiTaO3 substrate by hydrothermal method at 240oC at different reaction time. Linear two-dimensional finite element method (2D-FEM) was used to estimate the values of electromechanical coupling coefficient (kt) with different film thickness.
Figure 1 shows the XRD results of crystal structures of the obtained films at 3hr, 4hr and 5hr reaction time. Diffraction peaks correspond respectively to the (100), (111), (200) and (222) planes of an orthorhombic structure of standard KNbO3. When KOH value changed from 25ml to 40ml at 5hr results decreased in substrate LiTaO3 peak intensity compare to 3 &4 hr. Figure 2 shows simulation results of electromechanical coupling coefficient k31 according to KNbO3 film thickness. K31 increase with increasing film thickness and at 25μm, k31 = 0.169 (16.9%). Simulation results of PZT at thickness 25μm, k31=0.107 (10.7%). Simulation results show KNbO3 can be a good candidate to replace PZT by controlling film thickness.
Figure 1 shows the XRD results of crystal structures of the obtained films at 3hr, 4hr and 5hr reaction time. Diffraction peaks correspond respectively to the (100), (111), (200) and (222) planes of an orthorhombic structure of standard KNbO3. When KOH value changed from 25ml to 40ml at 5hr results decreased in substrate LiTaO3 peak intensity compare to 3 &4 hr. Figure 2 shows simulation results of electromechanical coupling coefficient k31 according to KNbO3 film thickness. K31 increase with increasing film thickness and at 25μm, k31 = 0.169 (16.9%). Simulation results of PZT at thickness 25μm, k31=0.107 (10.7%). Simulation results show KNbO3 can be a good candidate to replace PZT by controlling film thickness.