Optical properties of Fe-doped BaTiO3 films deposited on quartz substrates by sol-gel method

Abstract

Fe-doped BaTiO3 films were prepared on quartz substrates by sol-gel route. Linearly optical constants of the films were obtained by fitting transmittance spectra with Adachi’s model. With increasing Fe composition, refractive index n at 532 nm increases, single oscillator energy Ec and dispersion energy Ed increase, but optical band gap Eg decreases from 3.78 to 3.63 eV. In addition, nonlinear optical properties of the Fe-doped BaTiO3 films were analyzed by Z-scan method. Nonlinear optical responses of the BaTiO3 films were enhanced by Fe doping. For BaTi0.96Fe0.04O3 film, the third-order nonlinear refractive index coefficient γ, the nonlinear refractive index coefficient n2, the nonlinear absorption coefficient β and the third-order nonlinear susceptibility χ(3) are 1.98 × 10−13 m2/W, 1.03 × 10−6 esu, 1.33 × 10−7 m/W, 2.38 × 10−7 esu respectively. The nonlinearity is predominated by the nonlinear refractive behavior. These results suggest that Fe doping may tune the linear and nonlinear optical properties of BaTiO3 films, which indicates that Fe-doped BaTiO3 films are promising materials for applications in optical devices.