Ultrahigh-Density Nanowire Arrays Grown in Self-Assembled Diblock Copolymer Templates

TLDR

The study presents a simple, robust chemical route for fabricating ultrahigh‑density, high‑aspect‑ratio nanopore arrays via the equilibrium self‑assembly of asymmetric diblock copolymers. Array dimensions and lateral density are set by segmental interactions and copolymer molecular weight within this self‑assembly process. Direct current electrodeposition yielded vertical nanowire arrays with densities exceeding 1.9 × 10¹¹ wires per cm², markedly enhanced coercivities in ferromagnetic cobalt nanowires, and demonstrated that the copolymer approach is practical, parallel, compatible with existing lithography, and suitable for multilayer device fabrication.

Abstract

We show a simple, robust, chemical route to the fabrication of ultrahigh-density arrays of nanopores with high aspect ratios using the equilibrium self-assembled morphology of asymmetric diblock copolymers. The dimensions and lateral density of the array are determined by segmental interactions and the copolymer molecular weight. Through direct current electrodeposition, we fabricated vertical arrays of nanowires with densities in excess of 1.9 x 10(11) wires per square centimeter. We found markedly enhanced coercivities with ferromagnetic cobalt nanowires that point toward a route to ultrahigh-density storage media. The copolymer approach described is practical, parallel, compatible with current lithographic processes, and amenable to multilayered device fabrication.