Sol-gel fabrication of transparent ferroelectric (K,Na)NbO3/La0.06Ba0.94 SnO3 heterostructure

Lead-free K0.5Na0.5NbO3 (KNN) ferroelectric film and transparent La0.06Ba0.94SnO3 (LBSO) bottom electrode are fabricated on (001)-oriented SrTiO3 (STO) substrate by sol-gel. The characterization results confirm an epitaxial relationship between the films and the substrate, as well as a uniform structure and good crystallization quality of the films. The optical measurement shows that the film heterostructure exhibit a high transmittance with a maximum transmittance of similar to 80 %. The polarization-electric field (P-E) curves demonstrate that the twice remanent polarization value of the similar to 500 nm thick KNN film reaches up to 28 mu C/cm(2) under an electric field of 800 kV/cm, and the effective piezoelectric strain constant (d(33)*) is measured as 24.8p.m./V. The dielectric properties of the film are displayed, and the leakage behavior can be divided into three stages of Ohmic conduction, Schottky emission and Poole-Frenkel emission with increasing the applied electric field. This study indicates that transparent lead-free ferroelectric KNN heterostructures can be prepared using a cost-effective solgel method and shows promise for future applications.