An ellipsometric investigation of Ag/SiO<InlineEquation ID="Equ1"> <EquationSource Format="TEX">$\mathsf{_2}$</EquationSource> </InlineEquation> nanocomposite thin films

Dielectric properties of silver/SiO<Subscript>2</Subscript> 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. Copyright Springer-Verlag Berlin/Heidelberg 2003