Graphene can increase the sensitivity of micro-electro-mechanical system (MEMS) Sensors by up to 100 times, according to researchers at the Swedish KTH (Kungliga Tekniska Högskolan) Royal Institute of Technology in Stockholm.
“The advantage of using graphene membranes for piezoresistve Sensors is their extreme thinness,” Frank Niklaus, a professor at KTH, told EE Times. “The sensitivity of piezoresistive membrane sensors scale with reduced membrane thickness.”
Piezoresistive pressure Sensors typically integrate piezoresistive silicon resistors into sensor membranes, so that resistivity reads out strain. The MEMs version suspends the membrane over a cavity by etching out the silicon dioxide on the layer below it. KTH’s version suspends an extremely thin layer of graphene over a cavity etched into a silicon dioxide film on a silicon substrate. The extreme thinness of graphene membrane — sub-nanometer for monolayers — correspondingly increases the sensitivity of the electromechanical effect that makes the sensor work.
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