Abstract: Ferroelectric thin films, such as the classic lead zirconate titanate (Pb(Zr, Ti)O₃, PZT), are key constituents in high-performance actuators and transducers due to their excellent dielectric, ferroelectric, and piezoelectric properties. However, the piezoelectric performance of PZT thin films can vary significantly depending on their intrinsic material characteristics and evaluation conditions. Key influencing factors include film thickness and, as recent theoretical studies have highlighted, the size of the electrodes used during measurement. In this work, PZT thin films were fabricated on Si/Pt substrates via a Sol-Gel process using a hybrid PbO-TiO₂ buffer layer, enabling a systematic investigation of the combined effects of these parameters. By depositing PZT films of different thicknesses on the buffer layer, the role of the buffer in controlling film orientation and the influence of different grain sizes on film performance were analyzed. Experimental results demonstrate that increasing film thickness enhances the dielectric constant by up to 25% over a wide frequency range, leading to a corresponding improvement in the converse piezoelectric coefficient (d_{33, c}). More importantly, by sputtering electrodes of varying sizes on films with different substrate dimensions, it was verified that d_{33, c} increases with electrode diameter, and this trend is independent of both substrate size and film thickness, in agreement with previous simulation results. Notably, the d_{33, c} value measured using pad electrodes with a diameter of 1000 µ
m is comparable to the direct piezoelectric coefficient (d_{33, d}). Given the widespread use of electrodes of different dimensions in current research, this finding may provide a useful reference for the future evaluation of d_{33, c}.

Key words: converse piezoelectric performance, electrode diameter, degree of texture, PZT thin films