Directed Self Assembly of Mixed Nanowire Populations via Lithographic Microwells

Vertical nanowire arrays can be used for both energy harvesting and storage. Using assembly to create such arrays allows two populations to be mixed together, while standard fabrication limits the product to a single material. However in the absence of applied fields [1] or controlled drying conditions [2], nanowires typically assemble parallel to the surface, forming horizontal arrays. The Keating group has worked with anisotropic particles, called partially etched nanowires, which form arrays where up to 70% of wires were vertically oriented on a planar surface when their internal asymmetry was tuned to optimize van der Waals and electrostatic interactions [3]. Array quality was increased to nearly 100% standing when microwells were used to direct assembly [4].