OPTICAL AND MICROSTRUCTURAL CHARACTERIZATION OF SOL-GEL DERIVED CERIUM-DOPED PZT THIN-FILMS

Optical properties of cerium-doped PZT thin films on sapphire prepared by a sol-gel technique are investigated using both transmission and r eflection spectra in the wavelength range 200 to 900 nm. The refractiv e index, extinction coefficient and thickness of the film are determin ed from the measured transmission spectra. The packing density of the film is calculated from its refractive index using the effective mediu m approximation (EMA), and average oscillator strength and wavelength are estimated using a Sellmeir-type dispersion equation. Absorption co efficient (alpha) and the band gap energy (E-g) of each film compositi on are also calculated. Possible correlations of microstructure and ph ase formation behaviour with changes in band gap energy and other opti cal properties are discussed.