Integrating nanowires with substrates using directed assembly and nanoscale soldering

This paper describes a new methodology for integrating nanowires with micropatterned substrates using directed assembly and nanoscale soldering. Nanowires containing ferromagnetic nickel segments were fabricated by electrodeposition in nanoporous membranes. The nanowires were released by dissolution of the membrane and subsequently aligned relative to micropatterned substrates using magnetic field-directed assembly. After assembly, the wires were permanently bonded to the substrates using solder reflow to form low-resistance electrical contacts. This is the first demonstration of the use of nanoscale solder reflow to form low-resistance electrical interconnects between nanowires and substrates, and we demonstrated the utility of the strategy by fabricating a nanowire-based functional analog integrator.