The effects of metal concentration and annealing temperature on the optical properties of silver nanocomposite

Abstract

The optical properties of silver-silica nanocomposites (NCs) are studied at various annealing temperatures for two different silver concentrations. The NC thin films are prepared using co-sputtering of silver and silica using an energetic neutralized Ar beam, which are further annealed at various temperatures upto 900 °C under flowing Ar gas. Rutherford Backscattering Spectrometry is carried out to estimate the thickness of films and relative concentration of silver in the silica matrix. The Transmission Electron Microscope (TEM) images of the NC thin films show the presence of nano-particles (NP) in the as deposited thin films, which grow in size when annealed at 400 °C. The selected area diffraction (SAED) pattern and spacing between the lattice fringes confirm the presence of Ag NPs inside silica matrix. UV–Visible absorption spectroscopy is performed to investigate the optical absorption due to Localized Surface Plasmon Resonance of these Ag NP surrounded by silica matrix. The results indicate that the resonance peak position redshifts and the width of the peaks decreases with increasing annealing temperature for both concentrations. These results attribute to the growth of NPs due to diffusion-based growth and Ostwald ripening in different annealing regimes. The role of metal concentration in NC on the growth of NPs upon various annealing temperatures is discussed based on optical absorption results.