Optical and structural properties of Ag:Ta₂O₅ nanocomposites

In this paper, we investigated the optical and structural properties of the Ag:Ta₂O₅ nanocomposites. The nanocomposite films were prepared by magnetron co-sputtering of Ta₂O₅ with Ag chips. The transmission electron microscopy images clearly revealed that Ag nanoparticles were successfully produced by post-thermal annealing of the deposited films. The reflection spectra exhibited the surface plasmon resonance behavior. The photoluminescence (PL) spectra indicated that the Ag:Ta ₂O₅ nanocomposites exhibited larger PL intensity than pure Ag or pure Ta₂O₅. The PL enhancement is thought to be due to the surface plasmon resonance of Ag nanoparticles. From the spatial intensity distributions that were obtained by solving Maxwell equations using the three-dimensional, finitedifference time-domain method, we found that there was strong confinement of optical field near the Ag nanoparticle. This optical confinement effect makes it possible to exhibit the enhanced PL.