Ultrasensitive Room-Temperature Piezoresistive Transduction
in Graphene-Based Nanoelectromechanical Systems
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Abstract
The
low mass and high quality factors that nanomechanical resonators exhibit
lead to exceptional sensitivity in the frequency domain. This is especially
appealing for the design of ultrasensitive force and mass sensors.
The sensitivity of a nanomechanical mass and force sensor depends
on its mass and quality factor; a low resonator mass and a higher
quality factor reduce both the minimum resolvable mass and force.
Graphene, a single atomic layer thick membrane is an ideal candidate
for nanoelectromechanical resonators due to its extremely low mass
and high stiffness. Here, we show that by employing the intrinsic
piezoresistivity of graphene to transduce its motion in nanoelectromechanical
systems, we approach a force resolution of 16.3 ± 0.8 aN/Hz<sup>1/2</sup> and a minimum detectable mass of 1.41 ± 0.02 zeptograms
(10<sup>–21</sup> g) at ambient temperature. Quality factors
of the driven response of the order of 10<sup>3</sup> at pressures
∼10<sup>–6</sup> Torr on several devices are also observed.
Moreover, we demonstrate this at ambient temperature on chemical-vapor-deposition-grown
graphene to allow for scale-up, thus demonstrating its potential for
applications requiring exquisite force and mass resolution such as
mass spectroscopy and magnetic resonance force microscopy