Nanostructured porous SiO2 films for antireflection coatings

Thin films with a low refractive index play an important role in optics optoelectronics and microelectronics In this study we present nanostructured porous SiO2 films fabricated by using a glancing angle deposition technique These nanostructured porous SiO2 films deposited at an angle of 85 show very low refractive indices of 1 08 at 633 nm As an application a four-layer antireflection coating for visible wavelength is designed and fabricated using SiO2 material only The normal incidence reflectance of the antireflection coating averaged between 400 and 800 nm is about 0 04% The microstructure and the surface morphology are also investigated by using a scanning electron microscope (C) 2010 Elsevier B V All rights reserved