Effect of excess lead on the structural and electrical characteristics of sol-gel synthesized RuO2/Pb(ZrxTi1−x)O3/RuO2

In this study, we investigated the effect of excess lead on the structural and electrical characteristics of lead zirconate titanate [Pb(ZrxTi1−x)O3, PZT] thin films using the sol-gel spin coating method. X-ray diffraction, atomic force microscopy, X-ray photoelectron spectroscopy, and field-emission transmission electron microscopy were used to study the structural, morphological, chemical, and microstructural features, respectively, of these films as functions of the growth conditions (excess lead concentrations of 10, 20, and 25 mol%). The PZT thin film prepared at the 20 mol% condition exhibited the best electrical characteristics including a lower leakage current of 6×10−7 A/cm2 at an electric field of 50 kV/cm, a larger capacitance value of 1.92 μF/cm2 at a frequency of 1 kHz, and a higher remanent polarization of 20.1 μC/cm2 at a frequency of 5 kHz. We attribute this behavior to the optimal amount of excess lead in this PZT film forming a perovskite structure and suppressing the reaction of PZT film with RuO2 electrode.