An AC sensing scheme for minimal baseline drift and fast recovery on graphene FET gas sensor

This work reveals a new AC sensing scheme to achieve a fast recovery and minimal baseline drift of gas sensors based on graphene FETs. Compared with the state-of-art technologies, three distinctive advancements have been achieved: (1) first demonstration of using the AC phase lag signal between channel resistance and gate voltage as a sensitive gas detection scheme on graphene FETs; (2) achieving ultrafast baseline recovery speed (~10s) on a defect rich, chemical vapor deposition (CVD) grown monolayer graphene FET for various tested gases, including water, methanol and ethanol vapors, respectively, almost ten times faster than those of the conventional DC resistance measurements; (3) validation of the AC phase lag sensing principle by using both analytical simulation as well as experimental data. As such, the proposed sensing scheme and results could open up a new frontier of graphene FET based gas sensing devices for accelerated sensing speed in practical uses and fundamental researches.