Scalable fabrication of carbon-based MEMS/NEMS and their applications: a review

Abstract

The carbon-based micro/nano electromechanical system (MEMS/NEMS) technique provides a powerful approach to large-scale manufacture of high-aspect-ratio carbon structures for wafer-level processing. The fabricated three-dimensional (3D) carbon structures have the advantages of excellent electrical and electrochemical properties, and superior biocompatibility. In order to improve their performance for applications in micro energy storage devices and microsensors, an increase in the footprint surface area is of great importance. Various approaches have been proposed for fabricating large surface area carbon-based structures, including the integration of nanostructures such as carbon nanotubes (CNTs), graphene, nanowires, nanofilms and nanowrinkles onto 3D structures, which has been proved to be effective and productive. Moreover, by etching the 3D photoresist microstructures through oxygen plasma or modifying the photoresist with specific materials which can be etched in the following pyrolysis process, micro/nano hierarchical carbon structures have been fabricated. These improved structures show excellent performance in various applications, especially in the fields of biological sensors, surface-enhanced Raman scattering, and energy storage devices such as micro-supercapacitors and fuel cells. With the rapid development of microelectronic devices, the carbon-based MEMS/NEMS technique could make more aggressive moves into microelectronics, sensors, miniaturized power systems, etc. In this review, the recent advances in the fabrication of micro/nano hierarchical carbon-based structures are introduced and the technical challenges and future outlook of the carbon-based MEMS/NEMS techniques are also analyzed.

Nanocrystalline graphene at high temperatures: insight into nanoscale processes

“…[16][17][18] Graphitization at small length scales has gained importance because of the developments in carbon micro electro mechanical systems and nano electro mechanical systems (C-MEMS and NEMS). 19 A proper understanding of the graphitization process is important to tailor the structure and properties for different applications. Low-voltage transmission electron microscopy is a versatile tool for sub-angstrom level characterization of graphene and other related materials without inducing signicant damage to the material.…”

Structure-mechanical property relations of non-graphitizing pyrolytic carbon synthesized at low temperatures

“…The high hardness, low density, thermal stability, and biocompatibility of pyrolytic carbon (PyC) materials have made them promising candidates for ultra-strong super lightweight nanos-tructured materials, such as nanoarchitected metamaterials [1][2][3][4][5][6][7][8][9][10]. Such PyCs can be made at meter-scale through the pyrolysis of polymeric precursors, e.g.…”

“…Such PyCs can be made at meter-scale through the pyrolysis of polymeric precursors, e.g. polyacrylonitrile, phenol-formaldehyde (phenolic), and many others, through traditional polymer derived ceramics processing [6][7][8][9][10]. However, while previous reports of the mechanical properties of PyCs show that their hardness can either be enhanced or diminished as the pyrolysis temperature (T p ) is increased [11][12][13][14], structuremechanical property relations that are generalizable to PyCs synthesized using a variety of precursor carbon sources and processing techniques are not currently available.…”

Improved conductivity and capacitance of interdigital carbon microelectrodes through integration with carbon nanotubes for micro-supercapacitors

“…As an example of an effective microfabrication process, carbon-based microelectromechanical system (C-MEMS) technology is a unique platform combining different polymer fabrication techniques with pyrolysis or thermal degradation [21][22][23][24][25][26][27]. C-MEMS is a powerful approach to the large-scale microfabrication of carbon-based current collectors and electrodes for micro-supercapacitors [12,13,[28][29][30][31][32].…”