Self-Assembly in Large Molecular Weight Block Copolymers for Dual Metal Nanodot Patterning and Optical Applications

Block copolymers (BCPs) have the potential to revolutionise the manufacturing of nanotechnology primarily due to their ability to self-assemble into spatially ordered nanodomains, resulting in nanoscale patterning. High molecular weight co-polymers poly|(styrene-b-2-vinylprydine) (PS-b-P2VP) and polystyrene-b-polyethylene oxide (PS-b-PEO) are used to form self-assembled patterns that act as a polymer template. This polymer template is infiltrated with the inorganic materials gold (Au) and silver (Ag). Polymer template removal leaves behind inorganic metal nanodots that exhibits surface plasmonic (SP) resonance effects that are particularly applicable for optical applications. The shape and chemical composition of metallic nanodots can be controlled by UV ozone or plasma etching removal of the polymer. It is found that dual metal nanodot arrays of Au and Ag can be used to supress silicon reflectivity. Micelles of Au and Ag exhibit plasmonic resonance in the 400-600nm range that can be determined by the Au/Ag ratio. The transmission spectra for single metal nanodot arrays show SP dips at 430± 25nm for Au and 550 ±25nm for Ag. The resulting nanodot size, patterning and metal composition provides a low cost means of producing optical filters of tuneable plasmonic resonance effects.