Nanostructured porous SiO_(2) films for antireflection coatings

摘要

Thin films with a low refractive index play an important role in optics, optoelectronics, and microelectronics. In this study, we present nanostructured porous SiO_(2) films fabricated by using a glancing angle deposition technique. These nanostructured porous SiO_(2) films deposited at an angle of 85 deg 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 SiO_(2) material only. The normal incidence reflectance of the antireflection coating averaged between 400 and 800 nm is about 0.04percent. The microstructure and the surface morphology are also investigated by using a scanning electron microscope.