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Title: Air damping of atomically thin MoS{sub 2} nanomechanical resonators

Abstract

We report on experimental measurement of air damping effects in high frequency nanomembrane resonators made of atomically thin molybdenum disulfide (MoS{sub 2}) drumhead structures. Circular MoS{sub 2} nanomembranes with thickness of monolayer, few-layer, and multi-layer up to ∼70 nm (∼100 layers) exhibit intriguing pressure dependence of resonance characteristics. In completely covered drumheads, where there is no immediate equilibrium between the drum cavity and environment, resonance frequencies and quality (Q) factors strongly depend on environmental pressure due to bulging of the nanomembranes. In incompletely covered drumheads, strong frequency shifts due to compressing-cavity stiffening occur above ∼200 Torr. The pressure-dependent Q factors are limited by free molecule flow (FMF) damping, and all the mono-, bi-, and tri-layer devices exhibit lower FMF damping than thicker, conventional devices do.

Authors:
; ;  [1]; ;  [2]
  1. Department of Electrical Engineering and Computer Science, Case School of Engineering, Case Western Reserve University, 10900 Euclid Avenue, Cleveland, Ohio 44106 (United States)
  2. Department of Physics, College of Arts and Sciences, Case Western Reserve University, 10900 Euclid Avenue, Cleveland, Ohio 44106 (United States)
Publication Date:
OSTI Identifier:
22311096
Resource Type:
Journal Article
Resource Relation:
Journal Name: Applied Physics Letters; Journal Volume: 105; Journal Issue: 2; Other Information: (c) 2014 AIP Publishing LLC; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
77 NANOSCIENCE AND NANOTECHNOLOGY; CAVITIES; DAMPING; EQUILIBRIUM; LAYERS; MEMBRANES; MEMS; MOLYBDENUM SULFIDES; NANOSTRUCTURES; PRESSURE DEPENDENCE; RESONANCE; RESONATORS; THICKNESS

Citation Formats

Lee, Jaesung, Wang, Zenghui, Feng, Philip X.-L., E-mail: philip.feng@case.edu, He, Keliang, and Shan, Jie. Air damping of atomically thin MoS{sub 2} nanomechanical resonators. United States: N. p., 2014. Web. doi:10.1063/1.4890387.
Lee, Jaesung, Wang, Zenghui, Feng, Philip X.-L., E-mail: philip.feng@case.edu, He, Keliang, & Shan, Jie. Air damping of atomically thin MoS{sub 2} nanomechanical resonators. United States. doi:10.1063/1.4890387.
Lee, Jaesung, Wang, Zenghui, Feng, Philip X.-L., E-mail: philip.feng@case.edu, He, Keliang, and Shan, Jie. Mon . "Air damping of atomically thin MoS{sub 2} nanomechanical resonators". United States. doi:10.1063/1.4890387.
@article{osti_22311096,
title = {Air damping of atomically thin MoS{sub 2} nanomechanical resonators},
author = {Lee, Jaesung and Wang, Zenghui and Feng, Philip X.-L., E-mail: philip.feng@case.edu and He, Keliang and Shan, Jie},
abstractNote = {We report on experimental measurement of air damping effects in high frequency nanomembrane resonators made of atomically thin molybdenum disulfide (MoS{sub 2}) drumhead structures. Circular MoS{sub 2} nanomembranes with thickness of monolayer, few-layer, and multi-layer up to ∼70 nm (∼100 layers) exhibit intriguing pressure dependence of resonance characteristics. In completely covered drumheads, where there is no immediate equilibrium between the drum cavity and environment, resonance frequencies and quality (Q) factors strongly depend on environmental pressure due to bulging of the nanomembranes. In incompletely covered drumheads, strong frequency shifts due to compressing-cavity stiffening occur above ∼200 Torr. The pressure-dependent Q factors are limited by free molecule flow (FMF) damping, and all the mono-, bi-, and tri-layer devices exhibit lower FMF damping than thicker, conventional devices do.},
doi = {10.1063/1.4890387},
journal = {Applied Physics Letters},
number = 2,
volume = 105,
place = {United States},
year = {Mon Jul 14 00:00:00 EDT 2014},
month = {Mon Jul 14 00:00:00 EDT 2014}
}
  • We measure the energy relaxation rate of single- and few-layer molybdenum disulphide (MoS{sub 2}) nanomechanical resonators by detecting the resonator ring-down. Recent experiments on these devices show a remarkably low quality (Q)-factor when taking spectrum measurements at room temperature. The origin of the low spectral Q-factor is an open question, and it has been proposed that besides dissipative processes, frequency fluctuations contribute significantly to the resonance line-width. The spectral measurements performed thus far however, do not allow one to distinguish these two processes. Here, we use time-domain measurements to quantify the dissipation. We compare the Q-factor obtained from the ring-downmore » measurements to those obtained from the thermal noise spectrum and from the frequency response of the driven device. In few-layer and single-layer MoS{sub 2} resonators, the two are in close agreement, which demonstrates that the spectral line-width in MoS{sub 2} membranes at room temperature is limited by dissipation, and that excess spectral broadening plays a negligible role.« less
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