Evolution of structure and electrical properties of epitaxial BiFeO3 thin films through solution and annealing atmosphere

Solution derived high-quality epitaxial BiFeO3 (BFO) thin films, with robust spontaneous polarization, are still desired because of their advantages. Herein, epitaxial BFO thin films and SrRuO3 bottom electrodes are prepared on LaAlO3 substrates via chemical solution deposition (CSD) technique. The influences of precursor solution on the microstructure and electrical properties are investigated by using nitrate salt and acetate salt system. The XRD and P-E hysteresis loops results demonstrate that the BFO thin film prepared by acetate salt system as a relatively green CSD route shows good epitaxial characteristic and ferroelectric performances. In addition, the effect of the annealing atmosphere on the microstructure and electrical properties are studied for the acetate salt derived BFO thin films. The microstructure and defects chemistry are analyzed by SEM and XPS, the BFO thin film annealed in air shows better comprehensive ferroelectric performances with the lowest leakage current and enhanced ferroelectric polarization due to the improved microstructure and decreased defect concentrations. The results here thus provide an instructive approach to optimize the growth of solution-derived epitaxial BFO-based thin films.