| AVS 63rd International Symposium & Exhibition | |
| MEMS and NEMS | Thursday Sessions |
| Session MN+2D+NS-ThA |
| Session: | Focused Session on Atomic Layer Nanomechanics and 2D MEMS |
| Presenter: | Rui Yang, Case Western Reserve University |
| Authors: | H. Jia, Case Western Reserve University R. Yang, Case Western Reserve University P.X.-L. Feng, Case Western Reserve University |
| Correspondent: | Click to Email |
Micro/nanoelectromechanical systems (NEMS/NEMS) have demonstrated versatile device technologies for sensing applications by exploiting their miniaturized dimensions and increasing sensitivities upon scaling.1,2 However, quite limited flexural-mode resonators (mostly cantilevers and doubly-clamped beams) have been reported, with only fundamental-modes are often utilized that suffer from very low quality factors (Q<5) in viscous media.3-6
In this work, we experimentally demonstrate the operation of molybdenum disulfide (MoS2) nanoscale drumhead resonators (1–5µm in diameter, 50–60nm in thickness) in fluidic environment (water), which exhibit robust multimode resonances in the high- and very-high-frequency (HF/VHF) bands. We observe ~10 flexural modes up to ~150 MHz in water. The Q factors can easily exceed 10 for fundamental modes, and achieve as high as ~30 for higher modes.
Atomic-layer MoS2, an emerging two-dimensional semiconductor, has attracted tremendous attention due to its ultralight weight and high surface-to-volume ratio. These attributes suggest that MoS2 nanoresonators hold potential for ultrasensitive sensing capabilities even in fluids. Meanwhile, drumhead structure exhibits sealed air cavity and multimode resonance characteristics, which help maintain device performance in liquid.
The MoS2 resonators are directly immersed in water, and optothermally driven by an amplitude-modulated 405nm diode laser. The multimode resonances are interferometrically read out using a 603nm He-Ne laser. We observe ~10 flexural modes up to ~150 MHz with Q factors exceeding 10 for fundamental modes, and reach as high as ~30 for higher modes in water. We attribute the improved resonance performance (higher f and Q, as compared to cantilever beams) to the drumhead structure consisting of an air cavity on one side. We also demonstrate the degradation of resonance characteristics (f, Q dramatically drop) if water gradually leaks into the imperfectly-sealed nanodrum cavities.
[1] J.L. Arlett, et al., Nature Nanotech. 6, 2011.
[2] B.N. Johnson, et al., Biosens. Bioelectron. 32, 2012.
[3] J. Tamayo, et al., Ultramicroscopy 86, 2001.
[4] A. Vidic, et al., Ultramicroscopy 97, 2003.
[5]S.S. Verbridge, et al., Nano. Lett. 6, 2006.
[6] A.P. Davila, et al., Biosens. Bioelectron. 22, 2007.