Effect of deposition rate and heat treatment on microstructural, morphological, optical properties and ultra-fast laser-induced damage threshold of Al_2O_3-ZrO_2 pure and mixed thin films prepared by electron beam evaporation

摘要

Electron beam evaporation method was used to synthesize alumina, zirconia, and alumina-zirconia mixed thin films on the fused silica substrate. Rutherford backscattering spectroscopy was carried on to determine the stoichiometry and composition ratio of the prepared mixed thin films. Ultraviolet-visible-near infrared spectrophotometry was performed to measure the transmittance spectra of the deposited thin films. Yoldas expression was developed to calculate the porosity of mixed thin films. The approach for the modification of refractive index, extinction coefficient, porosity, and band-gap energy of fabricated thin films by the adjustment of the deposition rate and post-deposition annealing temperature was indicated. The growth of voids, pinholes, and separation between neighboring columns at higher annealing temperature is evident in the images of scanning electron microscopy. The results of X-ray diffractometry reveal the short-range order and amorphous nature of prepared alumina-zirconia mixed thin films. The optimized deposition conditions, for the improvement of the femtosecond laser-induced damage threshold of synthesized thin films were introduced.