OPTICAL CHARACTERISTICS OF AN INHOMOGENEOUS LAYER OF BARIUM TITANATE DOPED WITH EUROPIUM

Abstract

An algorithm for solving the inverse problem of multi-angle spectrophotometry of an inhomogeneous absorbing film based on polynomial representations of the density of the film material and its complex refraction coefficient is developed. The algorithm was applied to determine the spectral and spatial distributions of the refractive and absorption indices of a barium titanate film doped with europium. The film is deposited using a sol-gel technology on a silicon dioxide layer on a silicon substrate. The correctness of the obtained solution was verified by comparing the calculated and measured spectra of ellipsometric angles and spectra of reflectivity at normal incidence of light. A decrease in the wavelength corresponding to the edge of the intrinsic absorption band of barium titanate, an increase in the band gap of the material of the inhomogeneous layer, and a decrease in the concentration of europium over the layer thickness are found.