posted on 2021-06-18, 18:10authored byFan Ye, Arnob Islam, Teng Zhang, Philip X.-L. Feng
We
report on the experimental demonstration of atomically thin
molybdenum disulfide (MoS2)–graphene van der Waals
(vdW) heterostructure nanoelectromechanical resonators with ultrawide
frequency tuning. With direct electrostatic gate tuning, these vdW
resonators exhibit exceptional tunability, in general, Δf/f0 > 200%, for continuously
tuning the same device and the same mode (e.g., from ∼23 to
∼107 MHz), up to Δf/f0 ≈ 370%, the largest fractional tuning range in
such resonators to date. This remarkable electromechanical resonance
tuning is investigated by two different analytical models and finite
element simulations. Furthermore, we carefully perform clear control
experiments and simulations to elucidate the difference in frequency
tuning between the heterostructure and single-material resonators.
At a given initial strain level, the tuning range depends on the two-dimensional
(2D) Young’s moduli of the constitutive crystals; devices built
on materials with lower 2D moduli show wider tuning ranges. This study
exemplifies that vdW heterostructure resonators can retain unconventionally
broad, continuous tuning, which is promising for voltage-controlled,
tunable nanosystems.