Microstructure and Optical Characterization of Au/SiO2 Nano-Composite Multilayer Films

Au/SiO2 nano-composite multilayer thin films with different thickness were prepared on a quartz substrate by magnetron plasma sputtering. The microstructure, morphology and optical properties of the films were investigated by using TEM and optical absorption spectra. [Au/SiO2]×5 and [Au/SiO2] × 11 multilayer thin films have well-defined interface. The thickness of the multilayer was 60nm and 130 nm for the thin films with 5 and 11 layers, respectively. The optical absorption peaks due to the surface plasma resonance appeared at a wavelength of 560 nm for the both [Au/SiO2]×5 and [Au/SiO2]×11 thin films. The intensity of the absorption peak increased with increasing numbers of deposition layers. The optical absorption spectra of Au/SiO2 multilayer thin films are well agreement with the theoretical optical absorption spectra calculated from rewritten Maxwell–Garnett effective medium theory.