Photo-thermal process on BiFeO3 thin film

This study demonstrates that a photo-thermal process, namely a concurrently light illumination during annealing, is an effective method to develop a high-quality BiFeO3 (BFO) thin film. The wavelength-dependent light effect, which is determined by the photo absorption property of the sol-gel synthesized BFO solution, assisted in the decomposition of organic residues within the film during the thermal history. The photo absorption property of the BFO precursor varied with an exponential function of temperatures. By using a combination of an appropriate wavelength light illumination and a suitable temperature thermal annealing, the BFO film formed in a uniform dense microstructure with near-stoichiometric composition which was difficult to achieve with a traditional thermal process. We proposed the application of light illumination under thermal process would improve the reaction sequences of the constituent species as well as the crystallization mechanism of BFO, then providing the flexibility to control the film characteristics.