AVS 60th International Symposium and Exhibition
    MEMS and NEMS Tuesday Sessions
       Session MN+NS-TuM

Paper MN+NS-TuM6
Two-Dimensional (2D) MoS2 Semiconducting Crystal Nanomechanical Resonators with Frequency Scaling

Tuesday, October 29, 2013, 9:40 am, Room 102 A

Session: Micro and Nano Systems based on Carbon and Piezoelectric Materials
Presenter: J. Lee, Case Western Reserve University
Authors: J. Lee, Case Western Reserve University
Z. Wang, Case Western Reserve University
K. He, Case Western Reserve University
J. Shan, Case Western Reserve University
P. X.-L. Feng, Case Western Reserve University
Correspondent: Click to Email
We report the first demonstration of resonant nanoelectromechanical systems (NEMS) based on ultrathin molybdenum disulfide (MoS2) crystals down to only a few atomic layers, with measurements of resonances in the high frequency and very high frequency (HF/VHF) bands, and studies of frequency scaling pathways toward the ultrahigh frequency (UHF) and microwave regimes. Atomically-thin two-dimensional (2D) crystals have recently shown interesting promises for enabling new nanoelectronic and optoelectronic devices [1]. The unique mechanical properties of these 2D crystals, including excellent elastic modulus (~0.2-1TPa) and extremely high strain limits (~102-103 times higher than in 3D crystals), also make them attractive for 2D NEMS [2,3]. To date, most 2D NEMS have been based upon graphene, the hallmark of 2D crystals. 2D MoS2, an ultrathin crystal of transition metal dichalcogenides (TMDCs), has emerged as a new class of 2D layered materials beyond graphene. Unlike graphene being a semimetal, 2D MoS2 is a semiconducting crystal with a sizeable bandgap and hence opens up new device opportunities. In this work, we describe experiments on realizing drumhead-structured MoS2 NEMS resonators based upon suspended MoS2 diaphragms as thin as 6nm (9 layers of the crystal unit cell). We demonstrate resonators operating at up to ~60MHz in the VHF band at room temperature, with measurements of Brownian-motion thermomechanical noise spectra. We also measure quality (Q) factors of these MoS2 resonators and explore the dominating energy dissipation mechanisms in these 2D structures. The extensive measurements and analysis in this work with many devices establish MoS2 as a new material for frequency-scalable 2D NEMS resonators and transducers. Our study opens up possibilities for new types of NEMS, where the mechanical properties of 2D MoS2 can be coupled to its semiconducting attributes.

[1] Q. H. Wang, et al., Nature Nanotechnology 7, 699-712 (2012).

[2] R. A. Barton, et al., J. Vac. Sci. Technol. B 29, 050801 (2011).

[3] J. Lee, P. X.-L. Feng, Proc. IEEE Inter. Freq. Contr. Symp. (IFCS2012), DOI: 10.1109/FCS.2012.6243742