Optical properties of silver nanoparticles embedded in dielectric films produced by dc and rf magnetron sputtering

In this work it is reported the experimental production of silver-dielectric nanocomposites by the rf and dc magnetron sputtering techniques, as well as, the evolution of the plasmon resonance in silver nanoparticles as a function of the size of silver nanoparticles in the nanocomposites. Our nanocomposites are constituted by the intercalation of dielectric (Teflon, SiO2, TiO₂ or a-C) layers made by rf magnetron sputtering with layers of silver nanoparticles made by dc magnetron sputtering. Size of silver nanoparticles was modulated by changing the values of dc current of the plasma during deposition and keeping constant all the other parameters. High resolution transmission electron microscopy was used to observe the shape and size of nanoparticles. The chemical composition and crystalline structure of the materials were analyzed by X-ray photoelectron spectroscopy and X-ray diffraction, respectively. UV-visible spectroscopy in the 350-1100 nm range was used to study the plasmon-resonance evolution. Dipolar and Quadrupolar Plasmon resonance were observed and interpreted in terms of the Mie theory.