Bismuth ferrite (BiFeO3, BFO) is still widely investigated both because of the great diversity of its possible applications and from the perspective of intrinsic defect engineering in the perovskite structure. Defect control in BiFeO3 semiconductors could provide a key technology for overcoming undesirable limitations, namely, a strong leakage current, which is attributed to the presence of oxygen vacancies (VO) and Bi vacancies (VBi). Our study proposes a hydrothermal method for the reduction of the concentration of VBi during the ceramic synthesis of BiFeO3.Using hydrogen peroxide (H2O2) as part of the medium, p-type BiFeO3 ceramics characterized by their low conductivity were obtained. Hydrogen peroxide acted as the electron donor in the perovskite structure, controlling VBi in the BiFeO3 semiconductor, which caused the dielectric constant and loss to decrease along with the electrical resistivity. The reduction of Bi vacancies highlighted by a FT-IR and Mott-Schottky analysis has an expected contribution to the dielectric characteristic. A decrease in the dielectric constant (with approximately 40%) and loss (3 times) and an increase of the electrical resistivity (by 3 times) was achieved by the hydrogen peroxide-assisted hydrothermal synthesized BFO ceramics, as compared with the hydrothermal synthesized BFOs.
Keywords: bismuth ferrite; complex dielectric permittivity; hydrogen peroxide; hydrothermal synthesis; vacancy.