Plumbing the Depths of the Nanometer Scale

Nanometer-scale plumbing systems that can transport attograms of material are no longer a pipe dream. Carbon nanotubes (CNTs), with their extremely strong mechanical strength and nanometer-sized hollow cores, are ideal candidates for nanochannels. Experimental setup for investigating the mechanisms of mass delivery is demonstrated in this article. Two Cu-filled CNTs supported on a sample holder and a probe provide three different cases to investigate subjected to electric current, thermal transport, charges, and ionization. Shown here are the schematic of nanorobotic spot welding, time-resolved TEM images from video frames showing the flowing process. The copper core started to flow inside the carbon shells from the root to the tip as the bias voltage reaches up to 2.5 V. Also shown is the mass changes along with time. The mass flow rate is then drawn out from the fitting curve as approximately 120 ag/s. Correlation of the current density and the mass flow rate shows that the driven mechanism is electromigration. The mechanisms for filling and transport have been demonstrated and explained, but significant developments are required for complete system construction.