Synthesizing nanostructured crack-free thick films of Fe-doped lead zirconate titanate by sol–gel dip coating method

Abstract

Lead zirconate titanate is one of the most well-known ferroelectric oxides and has been widely used in nano/micro-electromechanical systems and piezoelectric industries. Doping the lead zirconate titanate thick films by Fe3+ as an acceptor dopant leads to hard lead zirconate titanate piezoelectrics for specific applications including high frequency transducers. In this article, Fe-doped lead zirconate titanate thick films with the thickness of 27 µm are synthesized by using a modified acetic acid/alcoholic based sol–gel method and applying diethanolamine as a complexing agent. Crystallographic measurements are performed considering lattice constants and lattice distortion of the films by means of X-ray diffraction. Pure perovskite phase is obtained by adding the dopant up to 5 at. % Fe. The tetragonal lattice distortion and lattice parameters decrease by adding Fe and reach to its minimum level of c t = 4.024 A and a t = 3.966 A at 3 at. % Fe. The surface morphology and grain size are surveyed using field emission scanning electron microscopy, which shows the reduction in grain size by adding the dopant. Polarization-voltage loops and dielectric constants of the films are calculated by electrical measurement and illustrate reduction in the polarization by increasing Fe dopant. The highest value of coercive voltage is achieved at 3 at. % Fe. Moreover, the lowest dielectric constant of 318 is obtained at 5 at. % Fe. Nanostructured crack-free Fe-doped PZT thick films are successfully prepared by using modified sol–gel route with different Fe dopant percentages (a) surface morphology of PF(3 %)ZT, (b) cross section of PZT thick film.