Li-doped LiBO2 and LiNbO3 thin films have been studied and their optical and electrical properties determined. With doping the ionic conductivity of the films was found to increase substantially. The highest conductivity obtained with the doped films was about 4.5×10−6 S cm−1. All the films exhibited a high degree of transmission in the spectral region from 350 to 2500 nm. The remarkable increase in the ionic conductivity coupled to the preservation of a high optical transmission makes this doping technique highly attractive for devising ion conductors that can be used in transmissive solid-state electrochromic systems or the so-called ‘‘smart windows.’’

No abstract

No abstract

Light can be used to excite surface plasmons if there are proper mechanisms for coupling with those surface plasmons. This coupling can usually be achieved via surface roughness or evanescent waves in attenuated total-reflection experiments. In the present work, we report evidence of the possibility of having a resonant optical absorption when a granular dielectric layer is deposited on a metallic surface. Very thin films of MgF2 of mass thickness up to 8 nm have been used as a discontinuous overcoat on Au films of 100 nm thickness. Reflectivity measurements with p-polarized light incident at 40° show a resonant-type absorption near 520 nm when the dielectric layer is added to the Au surface. As the MgF2 film grows thicker and becomes continuous this absorption feature is no longer prominent. To account for this phenomenon, an effective-medium theory is used to describe the optical behavior of the coated Au surface. By including mirror-image effects in the dipole approximation, basic features of experimental measurements can be reproduced.

A strong resonant absorption near 400 nm is found when minute quantities of W03 are deposited on Ag surfaces. In order to explain this behavior, a granular structure is assumed for the WOs overcoat on the metallic substrate. This phenomenon could arise from the coupling of light with surface plasma waves via the mirror-image effect. The W03 material by itself shows nonabsorptive behavior in the spectral region considered. Experimental evidence is provided by differential reflectance measurements from 350 to 1000 nm for WOJ overcoats with a mass thickness varying from 1.5 to 15 nm. A well-defined peak in the magnitude of the differential. reflectance is found, shifting from 390 to 410 nm with increasing overcoat thickness. The observed behavior is consistent with predictions by an effectivemedium theory for the granular WOs deposit, which takes into account the dipole-dipole interactions between particles and the mirror-image effect in the metallic substrate.