Study on the structural and optical properties of nanocrystalline bismuth ferrite (BiFeO3) thin films

摘要

Nanocrystalline Bismuth Ferrite (BiFeO3) thin films were deposited onto a glass substrate by sol-gel process. The as-fired film annealed at 250 degrees C was found to be amorphous that crystalized to hexagonal structure after annealing at 500 degrees C for 2h in air. The XRD pattern shows that the sample is polycrystalline in nature. The film average crystallite size as calculated from the XRD date was found to be 35.1 nm. The as-fired films show higher transmittance than the crystalized films. As annealing temperature increase the absorption edge of the films was found to be sharper and shifting towards the lower energy. The optical band gap was found to decreases while the refractive index increases as the films crystalized. Nanocrystalline BiFeO3 exhibits a characteristic luminescence spectrum with two maxima around 2.53 and 2.34 eV.