Enhanced electrical properties in ferroelectric thin films on conductive Au–LaNiO3 nanocomposite electrodes via modulation of Schottky potential barrier

Abstract

Metal-conductive oxide nanocomposite thin films are regarded as promising electrodes for ferroelectric devices to overcome the intrinsic drawbacks of conventional metal or conductive oxides electrodes. In this work, ferroelectric Pb(Zr,Ti)O₃ (PZT) thin films with a thickness of 240 nm were deposited on metal-conductive oxide nanocomposite Au–LaNiO₃ (Au–LNO) electrodes by a sol–gel method, and their microstructure and ferroelectric properties were investigated. It was observed that the PZT thin films fabricated on the Au–LNO bottom electrode exhibited enhanced ferroelectricity with the remnant polarization as high as 59.6 μC cm⁻², which was much larger than those on the Pt (20 μC cm⁻²) and the LNO (33 μC cm⁻²) bottom electrodes. The J–V characteristics fitted by the Schottky emission model revealed the lowest potential barrier height at the interface between the PZT thin film and the Au–LNO electrode. The low potential barrier height contributed to a thin spacing charge layer at the PZT/Au–LNO interface, which was beneficial to the switching of ferroelectric domains. Ultraviolet photoelectron spectroscopy (UPS) results revealed that the decrease of the Schottky potential barrier was understood by the different work functions of the bottom electrodes according to the semiconductor theory. The present work demonstrates that metal-oxide nanocomposite electrodes can effectively improve the electrical properties of ferroelectric films by modulation of the Schottky potential barrier height. In particular, the modulation of the Schottky potential barrier by using nanocomposite electrodes also provides meaningful guidance for designing high performance ferroelectric photovoltaic devices.