Monolithic carbon structures including suspended single nanowires and nanomeshes as a sensor platform

Abstract

With the development of nanomaterial-based nanodevices, it became inevitable to develop cost-effective and simple nanofabrication technologies enabling the formation of nanomaterial assembly in a controllable manner. Herein, we present suspended monolithic carbon single nanowires and nanomeshes bridging two bulk carbon posts, fabricated in a designed manner using two successive UV exposure steps and a single pyrolysis step. The pyrolysis step is accompanied with a significant volume reduction, resulting in the shrinkage of micro-sized photoresist structures into nanoscale carbon structures. Even with the significant elongation of the suspended carbon nanowire induced by the volume reduction of the bulk carbon posts, the resultant tensional stress along the nanowire is not significant but grows along the wire thickness; this tensional stress gradient and the bent supports of the bridge-like carbon nanowire enhance structural robustness and alleviate the stiction problem that suspended nanostructures frequently experience. The feasibility of the suspended carbon nanostructures as a sensor platform was demonstrated by testing its electrochemical behavior, conductivity-temperature relationship, and hydrogen gas sensing capability.

Geometrically Structured Nanomaterials for Nanosensors, NEMS, and Nanosieves

“…However, the nanomaterial is usually fabricated in contact with the substrate, it is difficult to achieve high temperature due to heat dissipation by the substrate. For this reason, the suspended structure of nanomaterials has been widely studied, which enables to make the gas‐sensing material operated at high temperature with minimized heat conduction to the substrate 203–210. Suspended nanomaterial gas sensor has been developed by directly growing the sensing materials on the suspended microheater, in hence a low power of 6 mW was reported in the gas sensor employing tin oxide (SnO 2 )‐ZnO hybrid nanomaterials (Figure 4e,f).…”

Fabrication of patterned graphitized carbon wires using low voltage near-field electrospinning, pyrolysis, electrodeposition, and chemical vapor deposition

“…However, there still remains a strong need for a high-resolution, high-throughput patterning method, applicable to a wider variety of polymer precursors, to manufacture thinner wires for C-MEMS and C-NEMS. In addition, an improved throughput of the NFES will help in manufacturing new classes of well-defined polymer and carbon micro/nanostructures for advanced applications in electrochemical sensing, energy storage, and stem cell research 18,[40][41][42][43][44][45] .…”

Suspended microstructures of epoxy based photoresists fabricated with UV photolithography

“…Recently, fabrication of suspended SU-8 layers by partial exposure at a wavelength of 365 nm has been demonstrated [19]- [21]. The limiting factor of this fabrication process is the narrow processing window (5±1 sec UV exposure) for the partial exposure [22].…”