Optical switching of porous anodic aluminum oxide films embedded with silver nanoparticles

Dielectric films embedded with two-dimensional (2-D) arrays of metal nanoparticles have been fabricated by electro deposition of silver into nanopores of anodic aluminum oxide (AAO) films. Their pore diameter and inter-pore spacing are 80 nm and 20 nm, respectively. With its photoconductivity, the specimen has a higher conductance when being illuminated by a 514 nm wavelength laser. This photoconductivity can be explained by improved electron transport due to plasmonic coupling among neighboring silver nanoparticles induced by light illumination. The 2-D photoconductivity is expected to enable applications which are not suitable for one-dimensional photoconductivity induced by plasmonic coupling of nanoparticles embedded in nanowires. The 2-D photoconductivity of metal-nanoparticle-embedded dielectric films are expected to facilitate optoelectronic integrated circuits in the future.