The work – performed by researchers from Massachusetts Institute of Technology, Harvard, University of California Riveriside and US Army Research Laboratory – integrates a graphene-based photothermoelectric detector on a micrmachined silicon nitride membrane.
Responses of 7 to 9V/W were achieved at a wavelength of 10.6-micron with a time constant of 23ms. The combination of thermal isolation and broadband infrared absorption from the silicon nitride membrane enable detection and imaging of blackbody targets at 300 to 500K.
The high carrier mobility of graphene is used to overcome noise, thereby removing the need for cooling and is sufficient to detect thermal radiation from a human target without cryogenic cooling.
In the future, advances could make the device even more versatile. The researchers say that a thermal sensor could be based on a single layer of graphene, which would make it transparent and flexible and the simple manufacturing would help reduce costs.
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