Influence of O2 partial pressure and annealing treatment on structural and optical properties of TiO2/SiO2 multilayer

We model and optimize a configuration of six-layer anti-reflective (AR) TiO2/SiO2 coatings on K9 glass substrates by the Mass software. TiO2/SiO2 multilayers were deposited by electron beam evaporation with different O2 partial pressures. The results show that the higher transmissivity is produced at high O2 partial pressure because of less oxygen vacancies needed in multilayers. The crystallite has a tendency to congregate, causing the increase in surface roughness, and the transmittance of TiO2/SiO2 films is decreased. The influence of the annealing on microstructure and properties of the TiO2/SiO2 multilayers is discussed and the dependence of their structural and optical properties on annealing temperature is explored. At 500°C, the mixed amorphous phase appears in the TiO2/SiO2 thin films. The decrease in transmittance of composite thin films with annealing temperature is related to the increased residual stress and damaged interface.