Excitation of plasmons in self-ordered arrays of aluminum and silver nanoconcaves within UV–IR spectral range

Abstract

Large-scale hexagonally aluminum nanoconcave arrays were synthesized by electrochemical anodization of aluminum using oxalic acid and mixtures of phosphoric acid and citric acid; which, in turn, were used as nanostructured substrates to control the plasmonic resonances of silver. Plasmonic properties of both systems were investigated based on specular reflectivity in the ultraviolet–visible–infrared range. We found that their optical reflectance was dramatically reduced as compared with unstructured films deposited by thermal evaporation that were used as references. At the same time pronounced reflectance dips were detectable in the 262–1077 nm wavelength range, which were ascribed to plasmonic resonances of first and higher orders. We propose that the use of nanostructured aluminum as a substrate can be extended for the control of plasmonic properties of other metals.