Fabrication and effect of annealing on optical properties of single and bimetallic periodic array of different noble metals

The fabrication and optical properties of anisotropic nanostructures such as nanorods and nanoprisms have attracted considerable interest in recent years due to the Localized surface plasmon resonance (LSPR) effect and tuneable optical properties. The quality of such structures play an important role since they are mainly used for chemical and biological sensing, nanomedicine and solar energy conversion applications which requires an inert dielectric layer to electrically isolate the nanostructure from corrosive electrolyte usually employed in many devices[1,2]. Thus the incorporation of plasmonic nanomaterials into different applications and optoelectronic devices requires chemically stable surfaces and also the protection of their unique optical properties[2]. Annealing is one of the approaches to change the quality of plasmonic nanostructures. We will present the design and fabrication details for electrodeposition single periodic array of different noble metals such as gold, silver, Nickel as well as semiconductor (CdSe) into the pores of an aluminium oxide membrane prepared by two step anodization. The optical properties of these structures before and after annealing have been characterised. The electrodeposition step will provide bimetallic gold and silver by employing the electrochemical deposition of Au/Ni or Au/Ag alloy nanorods into the pores of anodized aluminium oxide templates. Strong optical extinction of noble metal nanostructures at visible and near infrared (NIR) wavelengths based on collective excitation of conduction electrons near the surface as well as coupling of these plasmonic excitations in assemblies of nanostructures make them good candidates to scale down optical and optoelectronic devices to nanometric dimensions[1,2]. These pave the way to explore the potential of light manipulation in nanophotonic circuits and has already led to promising advances information processing, bio-sensing and many other optical technologies [2-6]. Finally w- propose an optoelectronic and photonic device for plasmonic optical antenna that can potentially be used for in situ chemical and biological detection and also Surface-Enhanced Raman Scattering (SERS).