Preparation and Optical Properties of TiO2/SiO2 bilayer antireflection film

Abstract

TiO₂ films were deposited on monocrystalline silicon wafers with radio frequency (RF) magnetron sputtering, and the effects of O₂ flow ratio on the films' stoichiometric ratio, phase composition, micromorphology and refractive index were investigated. The results showed that as O₂ flow ratio increased, O/Ti molar ratio in the film increased from 1.92 to 2.04, an anatase phase was gradually formed in the film although the substrate was not intentionally heat, the surface nanoparticles became larger, and the film's refractive index decreased first and then increased continuously. And a TiO₂/SiO₂ bilayer antireflection film was designed and prepared on the quartz glass substrate, of which the TiO₂ layer was composed of columnar particles vertically grown on the substrate, and the SiO₂ layer was amorphous. This film increased substrate's average transmittance in visible region (380–780 nm) by 0.7%, and the coated substrate's maximum transmittance reached 95.9% at 505 nm wavelength, which was 2.8% higher than that of the blank substrate. The photoelectric conversion efficiency of the solar cell covered by the bilayer sample increases by 0.35% slightly and the external quantum efficiency increases by 1.08% at 500 nm.