TITLE:
Effect of Substrate Temperature on Structural and Optical Properties of Au/SiO2 Nanocomposite Films Prepared by RF Magnetron Sputtering
AUTHORS:
Ahmed A. Belahmar, Ali Chouiyakh
KEYWORDS:
Gold Nanoparticles, Sputtering, Lattice Distortion, Substrate Temperature
JOURNAL NAME:
Open Access Library Journal,
Vol.4 No.8,
August
21,
2017
ABSTRACT: Silica films containing gold nanoparticles were grown by magnetron radio frequency (rf) sputtering technique under various deposition conditions. The structural and optical properties of the composite films deposited at 400℃ substrate temperature were compared with those deposited at room temperature. Effect of substrate temperature of AuNPs on micro structural properties of the Au/SiO2nanocomposite films, such as size, dislocation density (δ), strain (ε) and lattice distortion (LD) have been investigated. The face-centered cubic crystalline structure of Au nanoparticles inclusion in the amorphous silica dielectric matrix was confirmed using X-ray diffraction. The average grain size of AuNPs has been found in the range of 0.56 - 0.60 nm and 1.15 - 1.23 nm at 3 × 10﹣3 mbar and 2 × 10﹣3mbar argon pressure respectively. The δ, ε, LD values change inversely with the increasing of the substrate temperatures. These composites exhibit the optical features of a semiconductor with direct band gap. The band gap energy of 3.85 eV and 4.1 eV achieved for gold nanoparticles when the substrate temperatures increases from 25℃ to 400℃. A peak wavelength of the surface plasmon resonance band absorption (SPR) characteristic of gold nanoparticle was found around 500 nm for the sample deposited at 2 × 10﹣3 mbar and at 400℃ substrate temperature.