Optical characterization of ferroelectric Bi3.25La0.75Ti3O12 thin films
National Laboratory for Infrared Physics, Shanghai Institute of Technical Physics, Chinese Academy of Sciences, 500 Yu Tian Road, Shanghai 200083, P.R. China
Corresponding author: a email@example.com
Revised: 25 February 2004
Published online: 28 May 2004
Amorphous and crystalline Bi3.25La0.75Ti3O12 (BLT) thin films on vitreous silica and sapphire substrates are prepared from chemical solutions. Their optical properties are investigated by transmittance measurements at energies from 1.1 to 5.0 eV. A four-phase model consisting of air, surface rough layer, BLT, and substrate is used to simulate the measured transmittance spectra. The inverse synthesis method with a double Tauc-Lorentz (DTL) dispersion function is used to calculate the optical constants and film thicknesses. The dispersion of the refractive index in the transparent region agrees with Sellmeier's dispersion relation. The absorption edges of the BLT films are different in the amorphous and crystalline cases.
PACS: 78.20.Ci – Optical constants (including refractive index, complex dielectric constant, absorption, reflection and transmission coefficients, emissivity) / 78.66.Nk – Insulators / 78.68.+m – Optical properties of surfaces / 78.40.Ha – Other nonmetallic inorganics
© EDP Sciences, Società Italiana di Fisica, Springer-Verlag, 2004