Nano-soldering of magnetically aligned three-dimensional nanowire networks

Abstract

It is extremely challenging to fabricate 3D integrated nanostructures and hybridnanoelectronic devices. In this paper, we report a simple and efficient method tosimultaneously assemble and solder nanowires into ordered 3D and electricallyconductive nanowire networks. Nano-solders such as tin were fabricated ontoboth ends of multi-segmented nanowires by a template-assisted electrodepositionmethod. These nanowires were then self-assembled and soldered into large-scale3D network structures by magnetic field assisted assembly in a liquid mediumwith a high boiling point. The formation of junctions/interconnects between thenanowires and the scale of the assembly were dependent on the solder reflowtemperature and the strength of the magnetic field. The size of the assemblednanowire networks ranged from tens of microns to millimeters. The electricalcharacteristics of the 3D nanowire networks were measured by regular current–voltage (I–V) measurements using a probe station with micropositioners. Nano-solders, when combinedwith assembling techniques, can be used to efficiently connect and join nanowires with lowcontact resistance, which are very well suited for sensor integration as well asnanoelectronic device fabrication.