Electric-field assisted assembly and alignment of metallic nanowires

Abstract

This letter describes an electric-field assisted assembly technique used to position individual nanowires suspended in a dielectric medium between two electrodes defined lithographically on a SiO 2 substrate. During the assembly process, the forces that induce alignment are a result of nanowire polarization in the applied alternating electric field. This alignment approach has facilitated rapid electrical characterization of 350-and 70-nm-diameter Au nanowires, which had room-temperature resistivities of approximately 2.9 and 4.5ϫ10 Ϫ6 ⍀ cm.

Nanowires and Carbon Nanotubes

“…1d), which resolve individual Si NWs within the transferred BBF, show that the Si NWs recorded from different areas of this large substrate are well aligned along the upward expansion direction of the bubble. Indeed, the angular deviation of the Si NWs is less than 108 over the entire 150-mmdiameter wafer and represents a very substantial advance over previous studies [4][5][6][7][8] .…”

“…To realize such applications, researchers have directed considerable effort to the development of methods of assembly that might ultimately lead to integrated systems. For example, there have been studies of individual or small numbers of NW and NT devices prepared by random deposition, electric field directed assembly 4 , flowassisted alignment 5 , and selective chemical and biological patterning 6,7 , and up to centimetre-scale assembly of NWs using the Langmuir-Blodgett technique 8 . However, it is still unclear whether these methods can be extended to large-scale assembly of NWs and NTs on both rigid and flexible substrates with controlled alignment and density.…”

Supramolecular self-assembly codes for functional structures

“…There will be processes that are 'templated' in a structural sense and others that will be externally 'directed' by forces applied by humans or machines. Self-assembling monolayers of thiols on gold surfaces offer a very good example of templated self-assembly (Nuzzo et al 1987;Porter et al 1987;Bain & Whitesides 1988), whereas directed self-assembly could involve the application of external magnetic, electric or flow fields to induce or catalyse self-assembly (Messer et al 2000;Smith et al 2000;Whaley et al 2000;Huang et al 2001). It is interesting to consider how one might compute a figure of merit in the self-assembly processes that would measure the extent to which human intervention, templating or external energy are needed against the material value of the functions that the ordered structures or patterns produce.…”

Nano Electronic Materials

“…Valizadeh et al 7 and Smith et al 8 diameter, 4 µm long Au nanowires to be 35 Ω per wire 9 . Furthermore, they determined the "melting point" of these Au nanowires, the point at which they no longer conduct, to be 6.5 mA 9 .…”

“…Another approach that yields single nanowires in precise locations is electrochemical growth or evaporation 5 along the sidewall of a photoresist pattern. Some assembly attempts include chemical patterning of a substrate to selectively promote/discourage adhesion 6 , contacting individual wires with precisely placed electrodes using a focused ion/electron beam deposition technique 7 , and generating dielectrophoretic forces on nanowires in solution 8,9 . Modeling of the behavior of nanowires under dielectrophoretic forces has also been performed by Liu et al 10 .…”