ABSTRACT
In this chapter, some key characteristics of carbon-based nanomaterials and the role they play in enabling high-efficiency optical absorbers and mechanical resonators for nanoelectromechanical systems (NEMSs) are highlighted. In the first case, optical absorbers based on vertically aligned multiwalled carbon nanotubes (MWCNTs) are described that show an ultralow reflectance, which is 2 orders of magnitude lower compared to 238a reference material, Au-black, from a wavelength range of λ ~ 350–2500 nm. Reflectance measurements on the MWCNT absorbers after heating them in air to 400°C showed negligible changes in reflectance. The high optical absorption efficiency of the MWCNT absorbers over a broad spectral range, coupled with their thermal ruggedness, suggests that they have promise in solar energy harnessing applications, as well as thermal detectors for radiometry. In the second case, it has been shown that the mechanical and electrical properties of as-grown, vertically oriented carbon nanofibers (CNFs) are ideally suited for NEMS applications that derive benefit from the rugged and resilient mechanical properties of these nanostructures. The CNFs are synthesized using a plasma-enhanced chemical vapor deposition (PECVD) process and high-sensitivity optical interferometry is used to conduct mechanical resonance measurements. These resonator measurements show that the flexural resonances in the CNFs are in the very-high-frequency (VHF) regime up to 15 MHz, based on the typical geometries of the CNFs considered in these experiments. Our proof-of-concept measurements on the mechanical resonance characteristics of the CNFs suggest that they have exciting prospects for the resonant sensing and detection of radiation, adsorption, and other physical and/or biochemical processes.
