Sliding probe methods are designed for the in situ characterization of electrical properties of individual 1-D nanostructures. The key to achieving a high resolution is to keep the contact resistance constant by controlling the contact force and area between the specimen and the sliding probe. We have developed several techniques and tools including differential sliding, flexible probes, and specimen-shape-adaptable probes using nanorobotic manipulation. Compared with conventional methods, these sliding probe methods allow in situ characterization with a higher resolution than conventional methods. Furthermore, they are superior for local property characterization, which is of particular interest for heterostructured nanomaterials and defect detection.

Electromigration-based deposition (EMBD) is an additive nanolithography technology for the fabrication of three-dimensional (3D) nanostructures. Key techniques for extending the capability of EMBD have been tackled experimentally including the deposition against a non-conductive surface, shape control of the as-deposited nanostructure, and continuous mass feeding. The process is based on nanofluidic mass delivery at the attogram scale from metal-filled carbon nanotubes (m@CNTs) using nanorobotic manipulation inside a transmission electron microscope. By attaching a conductive probe to the sidewall of the CNT, it has been shown that mass flow can be achieved regardless of the conductivity of the object surface. Experiments have shown the influence of heat sinks on the geometries of the deposits from EMBD. By modulating the relative position between the deposit and the heat sinks using dual probes, it has been possible to reshape the deposits. The limited mass encapsulated inside a CNT requires a frequent change of them for depositing large structures. To realize continuous feeding, a reservoir will be an excellent solution. We have observed that the copper inside the neighbor CNTs to the CNT injector can be sucked into the injector. Although the mechanism is not well understood yet, electromigration and atom-by-atom wall-passing-through may be responsible to this phenomenon. This observation enabled a new path for the design of an EMBD system As a general-purposed nanofabrication process, EMBD will enable a variety of applications such as nanorobotic arc welding and assembly, nanoelectrodes direct writing, and nanoscale metallurgy.

Sliding probe methods are designed for the in situ electrical property characterization of individual one-dimensional (1D) nanostructures by eliminating the contact resistance between the fixed-end support and the specimen. The key to achieve a high resolution is to keep a constant resistance between the other end of the specimen contacting to the sliding probe. To achieve this objective, we have developed several important techniques including multipoint continuous sliding, flexible probes, and specimen-shape adapting based on nanorobotic manipulation inside a transmission electron microscope (TEM). With a copper-nanowire-tipped probe, we have shown that a flexible probe facilitates the contact force control. The adapting of the shape of a probe tip is significant for keeping a constant contact area between the probe and the specimen. This can be implemented by using a soft probe or a tip with a shape resembling the profile of the specimen. Here we show that by flowing copper from a nanotube probe against the specimen, it is possible to make a well adapted shape of the tip to the specimen after the copper cooled down. By avoiding stick-slip motion and controlling the contact force and area, it will be possible to keep a constant contact resistance between the sliding probe and the specimen, hence significantly improve the measurement resolution. Sliding probe methods are an in situ technique characterized by higher resolution and simplicity in setup as compared with conventional two- and four-terminal methods, respectively. Furthermore, it is superior for local property characterization, which is of particular interest for hetero-structured nanomaterials and defect detection.

Modes of melting and evaporation of metal at attogram level from individual carbon nanotubes (CNTs) are investigated experimentally using nanorobotic manipulation inside a transmission electron microscope. We compared the melting and evaporation induced by electric current, Joule heating, charge, and ionization. Experiments show that the most effective method is by positively ionizing the encapsulated metal, therefore, an electrostatic field can be used to guide the flow. Applications and potential applications of mass transport and deposition in nanofluidic systems have been presented including self-welding, actuation, and storage.

Nanorobotic spot welding using single-crystalline-copper-filled carbon nanotubes (CNTs) is investigated experimentally inside a transmission electron microscope (TEM). Controlled melting and flowing of copper inside nanotube shells are realized by applying bias voltages between 1.5 V and 2.5 V. The average mass flow rate of the copper was found to be 120 ag/s according to TEM video imaging (measured visually at approximately 11.6 nm/s through the CNT). Successful soldering of a copper-filled CNT onto another CNT using a nanorobotic manipulator shows promise for nano spot welding, which can play a role similar to its macro counterpart for the interconnection of nano building blocks for the assembly of nanoelectronic circuits and nanoelectromechanical systems (NEMS).