Large-Scale Hierarchical Organization of Nanowire Arrays for Integrated Nanosystems

The assembly of nanowires and nanotubes into arrays patterned on multiple length scales is critical to the realization of integrated electronic and photonic nanotechnologies. A general and efficient solution-based method for controlling organization and hierarchy of nanowire structures over large areas has been developed. Nanowires were aligned with controlled nanometer to micrometer scale pitch using the Langmuir−Blodgett technique and transferred to planar substrates in a layer-by-layer process to form parallel and crossed nanowire structures. The parallel and crossed nanowire structures were efficiently patterned into repeating arrays of controlled dimensions and pitch using photolithography to yield hierarchical structures with order defined from the nanometer through centimeter length scales. In addition, electrical transport studies show that reliable electrical contacts can be made to the hierarchical nanowire arrays prepared by this method. This solution-based process offers a flexible pathway for bottom-up assembly of virtually any nanowire material into highly integrated and hierarchically organized nanodevices needed for a broad range of functional nanosystems.