Optical properties of electron beam evaporated ZrO2:10 %SiO2 thin films: dependence on structure

Abstract

ZrO2:10%SiO2 thinfilms have been deposited on fused silica substrate by reactive electron beam co-evaporation technique at different oxygen partial pressure. The structural analysis shows tetragonal phase with residual tensile stress in the films. The intensity of the tetragonal t(110) phase are found increasing with increasing oxygen pressure. The optical band gap is found increasing from 5.06 eV to 5.28 eV because of increasing crystalinity of monoclinic phase, while the film grain size remains almost constant with increase of oxygen pressure, concludes that the crystallite or grain size has no effect on the optical properties of the films. The dispersion of the refractive index is discussed in terms of single oscillator Wimple-DiDomenico model. The dispersion energy parameter better known as structural order parameter are found increasing with the intensity of t(110) phase. It is observed that films having higher value of order parameter show lower surface roughness which concludes that the local microstructure ordering can predominantly influence the grain morphology which in turn can lead to better surface for higher value of order parameter.