Nanotube-Bridged Wires with Sub-10 nm Gaps

Abstract

We report a simple but efficient method to synthesize carbon nanotube-bridged wires (NBWs) with gaps as small as 5 nm. In this method, we have combined a strategy for assembling carbon nanotubes (CNTs) inside anodized aluminum oxide pores and the on-wire lithography technique to fabricate CNT-bridged wires with gap sizes deliberately tailored over the 5-600 nm range. As a proof-of-concept demonstration of the utility of this architecture, we have prepared NBW-based chemical and biosensors which exhibit higher analyte sensitivity (lower limits of detection) than those based on planar CNT networks. This observation is attributed to a greater surface-to-volume ratio of CNTs in the NBWs than those in the planar CNT devices. Because of the ease of synthesis and high yield of NBWs, this technique may enable the further incorporation of CNT-based architectures into various nanoelectronic and sensor platforms.

Nanocap array of Au:Ag composite for surface-enhanced Raman scattering

“…The additional enhancement is attributed to the large local electric fields generated in the nanogap adjacent nanocaps, which enhances the Raman excitation of the detecting molecule. When etching time increases over 60 s, the size of nanogap is larger than 20 nm, the Raman peak intensity gradually becomes weak, which is caused by the fact that the plasmon coupling between the adjacent nanocaps is weakened at larger separation distances [35,36]. These results indicate that in our system the maximum optimized SERS performance can be obtained in bimetal Au:Ag nanocap array with the 3 nm gaps size, and Au and Ag nanoparticles on the surface of PS along with the gaps between adjacent PS beads play the same role in SERS enhancement.…”

Nanoscale hybrid systems based on carbon nanotubes for biological sensing and control

“…Lee et al [60] reported biosensors based on nanotube-bridged wires (NBWs) that are prepared by electrodeposition and on-wire-lithography (OWL) techniques. The scheme and the SEM image of an NBW are shown in Figure 6a and b respectively.…”

“…( b ) SEM image of an NBW [60]. ( c ) Schematic diagram showing the DNA sensing experiment using an NBW-based FET [60].…”

“…( b ) SEM image of an NBW [60]. ( c ) Schematic diagram showing the DNA sensing experiment using an NBW-based FET [60]. ( d ) Real-time current measurement using NBW-based FET after the injection of non-complementary DNA and complementary DNA molecules [60].…”

“…( c ) Schematic diagram showing the DNA sensing experiment using an NBW-based FET [60]. ( d ) Real-time current measurement using NBW-based FET after the injection of non-complementary DNA and complementary DNA molecules [60]. ( e ) Schematic diagram depicting the intracellular calcium ion sensing experiment using nanoneedle shape transistor-based sensor (NTS).…”