An ellipsometric investigation of Ag/SiO\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$\mathsf{_2}$\end{document} nanocomposite thin films

Dielectric properties of silver/SiO2 nanocomposite thin films grown by high-pressure d.c. sputtering technique were studied by spectroscopic ellipsometry (300-800 nm). The dielectric behavior of the nanocomposite thin films largely depended on the particle size, its number density and the surrounding environments. The films showed semiconductor-like behavior up to a critical particle size and concentration, beyond which the films exhibited the typical surface plasmon resonance characteristics in their optical properties. The refractive index was also found to have a strong dependence on the particle size and its dispersion in the matrix. The results were found to be consistent with those obtained from UV-VIS optical absorbance data. Bruggeman effective medium theory was used to explain the experimental results.