Piezoelectric properties of epitaxial Pb(Zr,Ti)O3 thin films grown on Si substrates by the sol–gel method

•Pb(Zr,Ti)O3 (PZT) thin films were grown epitaxially on Si substrates by a sol–gel method.•Piezoelectric properties of polycrystalline and epitaxial PZT thin films on Si substrates were compared.•Epitaxial PZT thin film exhibits a smooth and dense cross-sectional structure.•Epitaxial PZT film showed a stable piezoelectric coefficient with low voltage dependence. In this study, we investigated the piezoelectric characteristics of the sol-gel Pb(Zr0.52Ti0.48)O3 (PZT) films deposited on two different types of substrates. Epitaxial PZT piezoelectric thin films were grown on ZrO2-buffered Si substrates, while polycrystalline PZT thin films were grown on conventional Pt/Ti/Si substrates by the sol–gel method. X-ray diffraction measurements revealed a cube-on-cube epitaxy on the buffered Si substrate. The piezoelectric coefficient (e31,f) of the epitaxial PZT thin films was investigated by measuring the tip displacement of PZT cantilevers, and the |e31,f | values were in the range of 8.9–12 C/m2. The voltage dependence of the |e31,f | values was more constant than that of the polycrystalline sol–gel PZT/Si cantilever. The epitaxial sol–gel PZT films thus exhibited good piezoelectric properties for applications in microelectromechanical systems devices.