Optical and photoluminescence properties of BiFeO3 thin films grown on ITO-coated glass substrates by chemical solution deposition

The optical and photoluminescence properties of the pure bismuth ferrite (BiFeO3) thin films deposited on ITO-coated glass substrates by chemical solution deposition methods were investigated. The optical bandgap of obtained BiFeO3 thin films annealed at 500 and 600 degrees C were confirmed to be 2.75 and 2.71?eV, respectively. The dependence of bandgap on annealing was discussed in terms of coarsening grain sizes as well as the existence of amorphous phases in the films. Furthermore, the evident photoluminescence of BiFeO3 thin films is observed. The near-band-edge emission located at 455.4 and 457.9?nm were identified for BiFeO3 thin films annealed at 500 and 600?degrees C, respectively, while the identical defect emission at 468.7 and 492.3?nm were confirmed for both BiFeO3 thin films, which were tentatively attributed to the defect states related with Bi3+ level and oxygen deficiencies inside the bandgap. However, more investigations are needed to classify the origin of BiFeO3 thin-film emission for further application.