Ultra-sensitive charge detection and latch memory using MoS2-nanoresonator-based bifurcation amplifiers

Abstract

Bifurcation amplifiers are known for their extremely high sensitivity to weak input signals. We implement a bifurcation amplifier by harnessing the Duffing nonlinearity in a parametrically excited MoS 2 nano-electromechanical system. We utilize the ultra-sensitive switching response between the two states of the bifurcation amplifier to detect as well as register charge-fluctuation events. We demonstrate openloop real-time detection of ultra-low electrical charge perturbations of magnitude <10 e at room temperature. Furthermore, we show latching of the resonator onto one of the two states in response to short-lived charge fluctuations. These charge detectors offer advantages of roomtemperature operation and tunable operation in the radio frequency regime, which could open several possibilities in quantum sensing.

Nanomechanical Resonators: Toward Atomic Scale

“…Since the electrostatic gate force tunes the static tension in the membrane, and such force tends to break the symmetry of the mode shape, it can be employed to increase the contribution to the nonlinear Duffing force associated with softening of the resonant mode. This can sometimes lead to the ability to realize zero effective nonlinearity for not too large displacement or to control the resonator in either a hardening or softening regime. ,, In addition, while the conventional wisdom for resonant sensors is to avoid nonlinear responses to preserve the linearity of the output, researchers have found that the response of NEMS resonant sensors can be enriched by exploiting the nonlinear effects. , All this is possible because the suspended nanomaterials can withstand a very high level of strain, allowing them to vibrate with very large amplitudes (compared with device size) and thus operate in deep nonlinear regimes; this feature is not readily available in bulk materials (such as Si, which is commonly used for MEMS resonators) that tend to fail at moderate strains.…”

“…The high mechanical strength of 2D materials allows 2D resonators to be driven at very high amplitudes, often more than the membrane thickness, leading to strong nonlinear effects. , In addition, the static tension tunes the frequency of different resonant modes. Tension-tunability of 2D membranes allows manipulating individual mode frequencies, nonlinearities, and mode coupling, which is not readily available in most MEMS devices.…”

“…NEMS resonators can detect very tiny changes in force and strain induced by a charge perturbation, and thus can function as highly sensitive electrometers (charge sensors). In one example, the excellent strain sensitivity of MoS 2 NEMS resonators, in conjunction with the bifurcation amplifier implementation, enabled real-time detection of charges on the order of 10 electrons at room temperature . Furthermore, the nonlinearity in the 2D NEMS resonators is exploited to implement a set-reset (SR) mechanical charge flip-flop which can record short-lived charge events.…”

“…125,210,211 In addition, while the conventional wisdom for resonant sensors is to avoid nonlinear responses to preserve the linearity of the output, researchers have found that the response of NEMS resonant sensors can be enriched by exploiting the nonlinear effects. 212,213 All this is possible because the suspended nanomaterials can withstand a very high level of strain, allowing them to vibrate with very large amplitudes (compared with device size) and thus operate in deep nonlinear regimes; this feature is not readily available in bulk materials (such as Si, which is commonly used for MEMS resonators) that tend to fail at moderate strains. Here we take a closer look at CNT resonators: The extreme aspect ratio of CNT and thus the large force response has important consequences for the dynamics of nanotube devices.…”

Probing Linear to Nonlinear Damping in 2D Semiconductor Nanoelectromechanical Resonators toward a Unified Quality Factor Model

“…Resonant two-dimensional (2D) nanoelectromechanical systems (NEMS) have demonstrated attractive device performance, such as ultralow power consumption, broad frequency tuning range, , large dynamic range, ultrahigh mass sensitivity, and high scalability toward large-scale arrays. , These attributes make them promising for various applications such as sensing, memory, computing, and radio frequency (RF) signal processing, as well as for fundamental research such as quantum experiments and coupling with other physical domains. − When the driving forces in NEMS resonators are increased, they can be driven from linear to nonlinear resonance regimes. − By leveraging the bistable states and large signal-to-noise ratio, these nanomechanical resonators with high vibration amplitudes provide unique promises for NEMS qubit, memory, − logic, frequency comb, Ising machine, , mass sensing, and RF filtering …”