In my PhD research, we used directed assembly methods to grow nanowires between targeted points in external circuitry. We performed transport measurements on as grown nanowires without any post-growth processes which are required to interface nanowires with external circuitry in other approaches. We also did detailed structural characterization on these nanowires. 

   Initially, we formed  interconnects dielectrophoretically from gold nanoparticles. We were able to form wires from cadmium sulfide (CdS) nanoparticles. These wires formed very fast which can be seen in this CdS wire formation movie. We also observed bursts of luminescence from CdS wires  as we continued to apply voltage after the formation of the wire.

We employed dielectrophoresis to form wires from gold nanorods (right image). We observed Coulomb Blockade to charge conduction in these wires due to their nanoparticulate structure.

   Recently, we developed a new technique that we call Directed Electrochemical Nanowire Assembly (DENA). This technique enables the growth of crystalline, metallic nanowires between targeted points in the external circuitry from simple salt solutions of the desired metals. 

   We were able to form single-crystal indium wires from indium acetate solution (left image) using DENA technique. You can watch a movie of the crystalline indium wire growth by clicking on the left image.

   We also demonstrated the DENA growth of near-single crystalline gold nanowires and their low-contact resistance interfacing with lithographic electrodes. We extended metallic wire formation from simple salt solutions to other metals such as lead, zinc, silver, copper, cobalt and nickel.