Microstructure and Crystallographic Orientation Dependence of Electrical Properties in Lead Zirconate Thin Films Prepared by Sol–Gel Process

Lead zirconate (PbZrO 3 ) thin films are grown on Pt(111)/Ti/SiO 2 /Si(100) substrates by sol–gel using precursor solutions with stoichiometric and 20 mol % excess Pb. Films with no preferred orientation and [111] pseudocubic texture (denoted as [111] pc ) are obtained by changing the drying temperature at the pyrolysis stage. Randomly oriented films were found to have a two-phase microstructure consisting of large rosette-type perovskite regions with a nanocrystalline phase located in between. The ratio of the rosettes increase to cover the entire surface of the films with the increase of Pb content. The films with [111] pc orientation have a uniform microstructure with micron size grains. The electrical properties of the films were influenced markedly by the microstructure and orientation of the films. The [111] pc oriented films exhibit a square-like double hysteresis loop with maximum polarization ( P max ) reaching 61×10 -6 C/cm 2 under 550 kV/cm, whereas stoichiometric films with no preferred orientation have a P max of 36×10 -6 C/cm 2 with slimmer hysteresis curves.