SPECTROSCOPIC ELLIPSOMETRY STUDIES ON ZINC OXIDE THIN FILMS DEPOSITED BY SOL–GEL METHOD WITH VARIOUS PRECURSOR CONCENTRATIONS
Abstract
Zinc Oxide thin films were deposited on glass substrates by sol–gel spin coating method. Zinc acetate dihydrate, 2-methoxyethanol and monoethanolamine were used as precursor, solvent and stabilizer, respectively. Zinc acetate dihydrate was used with different molar concentrations of 0.15, 0.25 and 0.5 M. Optical properties of ZnO thin films such as dielectric constants, absorption coefficient, Urbach energy and optical band gap energy were calculated by spectroscopic ellipsometry (SE) method. The effect of zinc acetate concentration on optical properties of ZnO thin films is investigated. ZnO thin film with Zn concentration of 0.25 M had the highest optical band gap. Wemple DiDomenico oscillator model was used for calculation of the energy of effective dispersion oscillator, the dispersion energy, the high frequency dielectric constant, the long wavelength refractive index and the free carrier concentration.
