Morphological and optical evolution of metallic oxide/Au nanoparticle hybrid thin film: High absorption and reflectance by plasmonic enhancement

Hybrid metal-oxide (MO)/metal nanostructures (MNSs) have been appealing in widespread optoelectronic devices due to their strong and tunable plasmonic activity encompassing selective scattering and absorption of wavelength depending upon the surface morphology and surrounding dielectric environment. In this paper, the various MO/Au NSs hybrid thin-films are fabricated via the solid-state-dewetting growth of Au NSs and sol-gel deposition of MO top-layers including ZrO_x, CeO_x, YO_x and AlO_x. Over 450% enhancements in maximum absorption are observed along with the peak redshift of 168 nm for the series of MO/Au NS films. The overall plasmonic properties undergo three regimes by the systematical control of film morphology: (I) Rapid enhancement, (II) Slow enhancement and (III) Decay. The optical evolution is correspondingly investigated with the assistant of finite-different time-domain (FDTD) calculation. This work may give an aid to the photo-electronic applications, such as photovoltaics, sensing and surface enhanced Raman scattering, based on hybrid MNSs especially on control of their plasmonic properties.