Computational Sub-10 nm Plasmonic Nanogap Patterns by Block Copolymer Self-Assembly

Abstract

Plasmonic nanoparticle (NP) arrays with narrow gaps have been suggested as an effective light collection solution for plasmonic structures. For an effective low-cost bottom-up strategy, block copolymer (BCP) self-assembly with evaporative metal-deposition is mentioned as one of the best effective ways to produce Au NP arrays with narrow gaps. In this paper, BCP self-assembly for nanopost-template arrays and metal-deposition over the nanotemplate surface for positional arrangement of Au NPs are described using a self-consistent field theory (SCFT) and a level-set method, respectively. According to the of BCP self-assembly simulation results, both the diameter of the cylinder post and gap size become larger due to the increase of polymerization degree (N). However, these parameters become smaller in terms of the increase of the Flory-Huggins interaction parameter χ. For plasmonic phenomena about a top-down incident wavelength of 600-nm, according to a rigorous coupled-wave analysis (RCWA), although the electric field around a single spherical post becomes larger at smaller diameter, there is no top-down plasmonic phenomenon at a gap size of 10-nm between nanoposts.