Researchers from Harvard University have made semiconductor nanowires (NWs) and carbon nanotubes using a ‘bottom up’ method. Their solution-based process shows promise in providing building blocks for the assembly of hierarchically organized nanodevices like integrated electronic and photonic systems.
The technique has been demonstrated with the production of arrays from silicon nanowires made by nanocluster-catalysed chemical vapour deposition. 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.
The crossed-nanowire array structures could be used as nanoscale light-emitting diode sources and as logic and memory arrays for nanocomputing.