A fast and sensitive room-temperature graphene nanomechanical bolometer

Abstract

Bolometers are a powerful means of detecting light. Emerging applications demand that bolometers work at room temperature, while maintaining high speed and sensitivity, properties which are inherently limited by the heat capacity of the detector. To this end, graphene has generated interest, because it has the lowest mass per unit area of any material, while also possessing extreme thermal stability and an unmatched spectral absorbance. Yet, due to its weakly temperature-dependent electrical resistivity, graphene has failed to challenge the state-of-the-art at room temperature. Here, in a departure from conventional bolometry, we use a graphene nanoelectromechanical system to detect light via resonant sensing. In our approach, absorbed light heats and thermally tensions a suspended graphene resonator, thereby shifting its resonant frequency. Using the resonant frequency as a readout for photodetection, we achieve a room-temperature noise-equivalent power (2 pW Hz−1/2) and bandwidth (from 10 kHz up to 1.3 MHz), challenging the state-of-the-art.

Nonequilibrium thermodynamics of acoustic phonons in suspended graphene

“…Recently, several optomechanical techniques to characterize the time-dependent heat transport in suspended 2D materials have been developed [19][20][21][22]. Here, we demonstrate the use of an optomechanical technique to distinguish two thermal expansion force contributions with different time-constants and opposite signs.…”

Ultrathin 2 nm gold as impedance-matched absorber for infrared light

“…Thereby, they exploit the conversion of the absorbed photothermal power to either a change in electrical resistance or electric potential, as in bolometers or pyroelectrics and thermocouples, respectively 1 . More recently, microelectromechanical and nanoelectromechanical systems (MEMS/NEMS) have demonstrated exceptional potential as IR and THz detectors due to strong photothermally-induced detuning of their mechanical resonance frequency [7][8][9][10][11][12][13][14] .…”

“…A progressive solution to improve the spectral range of detection has been to use a stack of plasmonic structures with differing lateral size; nonetheless, the bandwidth of these sensors remains limited e.g., from 0.8 to 1.3 THz 21 . A most recent thrust toward the ultimate limit of uncooled detection has been to employ the exceptional properties of 2D materials as graphene 22 , even making the detector itself the primary absorber, for example, as uncooled NEMS resonator 8 . However, due to graphene's low absorptivity in the near-IR to mid-IR of only 2.3% 23,24 , modifications using plasmonic metastructures are still required 25 , limiting the absorber again to a certain bandwidth.…”

Large Suspended Monolayer and Bilayer Graphene Membranes with Diameter up to 750 µm

“…graphene) has been proposed to reach the ultimate performance. These include desalination 23 , DNA sequencing 24,25 , pressure sensors 26 , temperature sensors 27 , gas sensors 28 , bolometers 29 . For most of these applications, having extreme aspect ratio membranes, i.e.…”