Paper NS-ThP7
Dielectrophoretic Manipulation of Nickel Nanowires

Thursday, November 13, 2014, 6:00 pm, Room Hall D

Nanowires have received much attention because their high aspect ratio, shape anisotropy, relatively large surface area and particular electron transport properties. Furthermore, given to the low electrical current level usually present in the nanowires and their high sensitivity to the environment, they can be used as sensors devices. Dielectrophoresis (DEP) is a deposition method of electrically neutral particles based on the application of alternating electric field between electrodes. In this work, 80 nm–thick aluminum electrodes were deposited on a 300 nm–thick SiO₂ layer grown on n⁺ – type silicon wafer using optical lithography and lift-off. After electrodes fabrication, nickel nanowires (NiNW) (length of 4 µm and diameter of 35 nm), obtained by electrodeposition, were manipulated and defined between the electrodes using DEP. Electrical parameters of DEP deposition – like frequency, electric potential, NiNW concentration and process time – as well as electrodes geometry were studied to investigate deposition efficiency. Preliminary results show best selection of electrical parameters and electrodes geometry that optimizes the nanowires deposition. For suitable parameters, the efficiency of DEP deposition is up to 90%. To characterize NiNW electrical properties, electrical current through the nanowires was measured as the voltage between electrodes. Initially, a Schottky-like contact is present and contact sintering under forming gas (92% of N₂ and 8% of H₂) at 450 ^oC was taken to reduce the eletrodes-NiNW contact resistance down to the NiNW resistance (~ 1k Ω). Finally, this method for nanowire deposition and electrical contact reduction has a suitable throughput and is a key for electric characterization of nanowires and fabrication of nanowire-based devices.