A flexible graphene FET gas sensor using polymer as gate dielectrics

We have successfully demonstrated a Graphene Field Effect Transistor (GFET) gas sensor on a flexible plastic substrate with a sensitivity of 0.00428ppm^-1 (ΔR/R₀) for ammonia. Compared with the state-of-art technologies, four distinctive advancements have been achieved: (1) first demonstration of a flexible graphene FET gas sensor; (2) a new fabrication process to achieve embedded-gate GFET on a flexible substrate; (3) proof of utilizing polymeric materials of parylene and polyethylenimine (PEI) as gate dielectrics and channel dopant for graphene FETs, respectively; and (4) validation of a gas sensing mechanism utilizing the real-time, n-type graphene doping process induced by the exposure of graphene FET to the targeted gases. As such, the proposed sensing scheme/platform could open up a new class of research in graphene-based, flexible gas sensing systems.