SHORT-RANGE ORDERED NANOHOLE ARRAYS IN OPTICALLY THIN GOLD FILMS

摘要

Since the discovery of extraordinary optical transmission, sub-wavelength nanohole periodic arrays in metal films have been widely studied for basic understanding and optimization of their optical properties. While huge literature focuses on optically thick metal films perforated with periodic nanohole distributions, a systematic knowledge of the effects of the short-range order on the optical response of nanohole arrays is still to be gained. This issue is of particular applicative interest in nanophotonics due to the possibility of using low cost and large-area deposition approaches, such as the self-assembly based colloidal lithography technique. In this study, we present nanohole arrays fabricated by electrostatic-driven self-assembly of negatively charged polystyrene nanospheres adsorbed onto a positively charged polydiallyldimethylammonium (PDDA) monolayer. Salt-free solutions of polystyrene nanospheres with diameter of 80 nm are considered to maximize the bead-to-bead electrostatic repulsion. The resulting short-range ordered nanohole distributions in optically thin (i.e., 20 nm thick) gold films are characterized with a focus on nanohole-distribution, optical response and refractometric sensing performance.