Design and fabrication of a topographic template for block copolymer self-assembly into archimedean spiral structure and its handedness control

Abstract

Theoretical and experimental studies of plasmonic nanostructures have been investigated extensively in the last few decades, fueled by its potentials in novel application areas. Among various nanostructures, Archimedean spirals have recently shown some unique and promising plasmonic properties but their applications have been limited by its fabrication methods. High resolution lithographies that have been used hitherto to produce such complex nanostructures are too costly and slow for large scale productions. Here, we report a novel, all bottom-up fabrication method of Archimedean nanospirals using block copolymers. Through a series of processes, an asymmetric defect is intentionally introduced into a topographic circular trench to induce block copolymer self-assembly into spirals. Furthermore, the handedness of the spirals can easily be controlled by modifying a single step in the fabrication process. This cost-effective and scalable alternative produces a well-arranged grid of Archimedean spirals of high yield and high handedness selectivity. With further studies, this nanostructure is expected to have plasmonic applications in areas such as second harmonic generation and polarization analyzers.