Structure and Optical Properties of 0.1BiFeO3-0.9SrBi2Nb2O9 Thin Films Using a Modified Sol-Gel Technique

Fe-doped SrBi2Nb2O9 precursor solution was synthesized using bismuth nitrate Bi(NO3)3·5H2O, strontium nitrate Sr(NO3)2, iron nitrate Fe(NO3)3·9H2O, and niobium ethoxide Nb(OC2H5)5 as starting materials, ethylene glycol monomethyl ether (C3H8O2) as the solvent. 0.1BiFeO3-0.9SrBi2Nb2O9 thin films were prepared on fused quartz substrates using sol-gel processing. The surface morphology and crystal structure and optical properties of the thin films were investigated. The thin film annealing at 400°C were found to be amorphous, and the thin films crystallize to a perovskite structure after a post-deposition annealing at 600°C for 1 h in air. The grain of thin film was evenly distributed. The thin films exhibit the designed optical transmission, while the optical transition is indirect in nature. Their optical band gap is about 2.5 eV.