Self-limited grain growth, dielectric, leakage and ferroelectric properties of nanocrystalline BiFeO3 thin films by chemical solution deposition

In this study, the growth mechanism of nanocrystalline BiFeO3/Pt/Ti/SiO2/Si thin films by chemical solution deposition has been investigated through isothermal annealing, and the dielectric, leakage and ferroelectric properties have also been studied in detail. The derived thin films show self-limited grain growth, which can be described well by a relaxation model, and the microstrain evolution follows exponential decay behavior. The dielectric constant and the loss behaviors have been investigated, and different contributions are expected for different thin films. The leakage current density behavior shows that conduction mechanisms are dominant, with the ohmic mechanism, the space-charge-limited current mechanism and the Fowler-Nordheim tunneling mechanism in low, middle and high electric fields, respectively. The behaviors of the ferroelectric coercive field and the polarization have also been investigated and found to be dominated by different factors for different samples. The results will provide an instructive route to optimize BiFeO3-based thin films grown using the chemical solution deposition method. (C) 2012 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.