Towards nanotube fountain pen

A nanotube fountain pen (NFP) is designed for the fabrication of three-dimensional (3D) complex nanostructures by adding a reservoir to the injector for electromigration-based deposition (EMBD). This enhanced EMBD technique is prototyped using a metal-filled carbon nanotude (m@CNT) as an pen-tip injector and a network of m@CNTs as a reservoir for continuous mass feeding. The deposition is based on nanofluidic mass flow from the pen-tip nanotube and the continuous mass feeding is implemented by inter-nanotube mass transport of the encapsulated metals. Experimental investigations have been performed using copper-filled CNTs using nanorobotic manipulation inside a transmission electron microscope. The threshold energy for mass delivery and the sizes of nanotube openings are co-related and the size-dependence of the fabricated nanostructures to the nanotubes is revealed. Furthermore, layer-by-layer prototyping processes are developed, and metallic nanostructures with larger dimensions are deposited using a single nanotube. As a general-purposed nanofabrication process for complex metallic nanostructures, nanotube fountain pen will be a key tool to scale up EMBD-based nanostructures.