Study of the Optical Properties of Bi3.15Nd0.85Ti3O12 Ferroelectric Thin Films

The optical properties of Bi3.15Nd0.85Ti3O12 (BNdT) ferroelectric thin films were stlidied. The BNdT thin films were deposited on Pt/Ti/SiO2/Si substrates by using a sol-gel technique. The ellipsometric spectra of the BNdt thin film were measured and investigated in the photon energy range of 1.5 - 4.5 eV. The ellipsometric spectral data were fitted by using the four-phase layer structure model and the Forouhi-Bloomer (FB) model, which was used to describe the optical dispersion relation of the sample. The optical constants of the sample were obtained by using a data analysis based on Taue's principle and showed that the direct band gap of the BNdT sample existed at 3.89 eV.