Structural Transformations of PZT 53/47 Sol-Gel Films on Different Substrates Driven by Thermal Treatments

PbZr0.53Ti0.47O3 (PZT) thin films were obtained by sol-gel synthesis, deposited by spin coating on ITO-coated float glass and Si wafer, and subjected to different thermal treatments. Their thermal structural evolutions have been studied by X-ray diffraction (XRD), scanning electron microscopy (SEM), and atomic force microscopy (AFM). The growth of ferroelectric perovskite phase, occurring for the highest annealing temperatures, depends on the substrate, being observed only on ITO substrate, while pyroclore phase, not ferroelectric, grows on Si substrates. The electrical properties of the perovskite phase have been investigated, on the nanoscale, by using electric force microscopy (EFM). It reveals asymmetric responses for induced polarization persistence, which can be related to phenomena of intrinsic polarization regarding the films, which changes as a function of the annealing temperature and of the duration of the annealing processes.