The effects of Mn doping on the optical properties of chemically deposited BiFeO3 thin films

A series of Mn-doped BiFeO3 (BFO) thin films were prepared on Pt/Ti/SiO2/Si(111) substrates using a chemical solution deposition method. The structural and optical properties of the Mn doped BFO thin films were studied by X-ray diffraction, Raman spectroscopy and ellipsometric spectroscopy. The X-ray diffraction analysis shows that the films have a single perovskite structure and that a phase transition appears with increasing of the Mn content. The Raman scattering spectra reveal that there are two additional peaks at around 480 and 620cm−1 for the Mn-doped BFO samples comparing to the undoped one, indicating the existence of orthorhombic phase. Ellipsometric spectroscopy measurements were carried out in the spectral range of 1–5eV and the experimental data fitted based on the Tauc–Lorentz model using two oscillators. The optical constants (refractive index n and extinction coefficients k) of the Mn-doped BFO thin films were determined. Moreover, the band gap was found to decrease with increasing of the Mn content. •A series of Mn doped BiFeO3 thin films were prepared.•Raman scattering and ellipsometric spectral measurements were carried out.•The optical constants of the Mn doped BiFeO3 samples are determined.