Electrically tunable single- and few-layer MoS ₂ nanoelectromechanical systems with broad dynamic range

Abstract

Atomically thin semiconductor resonators vibrating at radio frequencies with exceptional tunability and broad dynamic range.

Frequency Tuning of Graphene Nanoelectromechanical Resonators via Electrostatic Gating

“…For the same characteristic length and built-in strain, the circular device gives higher resonance frequency than the doubly clamped device does, since its circumference-clamped structure provides higher spring constant and smaller effective mass. These correlations for both cases agree with the results from previous models [ 6 , 9 , 10 , 19 , 20 , 21 , 22 , 23 , 24 ] at gate voltage V g = 0 V. To enable resonance frequency above gigahertz, f res > 1 GHz, built-in strain ≈0.25% with length smaller than 0.4 μm or built-in strain ≈0.05% with length smaller than 0.18 μm are required for doubly clamped graphene resonators. For circular drumhead resonators to achieve f res > 1 GHz, it needs a built-in strain ≈0.05% with a diameter smaller than 0.22 μm or a built-in strain ≈0.25% with a diameter smaller than 0.6 μm.…”

“…For convenience, we use a polar coordinate for the circular drumhead that closely matches the device geometry. The elastic energy stored in the stretched membrane U el,c can be obtained by [ 19 , 25 ] where R , ν , ε 0, r , ε 0, θ are radius, Poisson’s ratio, initial radial strain, initial tangential strain, respectively. Similar to the doubly clamped case, we assume that the curvature of the static deflection forms the parabolic shape, and it has the maximum static deflection at its center due to symmetry.…”

“…The reported frequency tuning results in the electrostatic scheme to date, however, exhibit complicated behavior including frequency downshifts and upshifts [ 6 , 7 , 8 , 9 , 10 , 11 , 12 , 13 , 14 , 16 ]. Several attempts have been made to develop frequency tuning models that can be used to describe and explain the precise tuning mechanisms of devices [ 6 , 9 , 10 , 19 , 20 , 21 , 22 , 23 , 24 ]. So far, however, these models are not sufficient to comprehensively explain the complicated frequency tuning behavior and the device coupling mechanisms.…”

Recent Progress on Irradiation-Induced Defect Engineering of Two-Dimensional 2H-MoS2 Few Layers

“…Few-layer MoS 2 were fabricated into two-dimensional nanoelectromechanical systems (NEMS) as ultralow-power, high-frequency tunable oscillators and ultrasensitive resonant transducers [152]. These devices can operate in the very high frequency band (up to ∼120 MHz).…”

Electronic Modulation of Near-Field Radiative Transfer in Graphene Field Effect Heterostructures

“…[15][16][17][18] Two-dimensional materials offer the capability to alter the surface dielectric function by electronic tuning of the free carrier concentration in a fast, controllable, and reversible manner without restrictions in operating temperature. [19][20][21][22][23][24][25] Despite this capability, achieving even modest modulation of far-field radiative flux is challenging as thermal radiation is broadband. In the near-field, however, thermal radiation is primarily due to resonant coupling of narrowband surface modes, such as plasmons or phonon-polaritons.…”