Anisotropy in the optical absorption of Ag–SiO2 thin films with oblique columnar structures

Abstract

An attempt has been made to clarify the anisotropy in the optical absorption and nanostructure of thin films prepared by oblique codeposition of Ag and SiO₂. At a low concentration of Ag, the columnar structure grows toward the incident direction of vapor flux of SiO₂, and Ag is dispersed in that structure as small metallic particles. An inhomogeneous distribution of Ag particles is obtained when Ag is deposited from the side of the normal to the film surface opposite to that of the incident direction of SiO₂ flux. The optical transmittance is strongly dependent on the angle of incidence and the polarization of the incident light due to the effects of the small Ag particles embedded in the oblique columnar structure. The anisotropic optical absorption of Ag and SiO₂ hybrid films can be used as an inorganic polarizer.