Electrical Kinetic\nModel of a Hydroxylated Graphene\nFET Gas Sensor

Graphene transistor sensors, with advantages such as\nfacile surface\nfunctionalization and high sensitivity, have gained extensive research\ninterest in gas detection applications. This study fabricated back-gated\ngraphene transistors and employed a hydroxylation scheme for the surface\nfunctionalization of graphene. On the basis of the interaction mechanisms\nbetween gas molecules and graphene’s electrical properties,\na compact electrical kinetics model considering the gas–solid\nsurface reaction of graphene transistors is proposed. The model can\naccurately predict the electrical kinetic performance and can be used\nto optimize sensor characteristics. The bias condition of a higher\nresponse can be rapidly determined. In addition, the density of hydroxyl\ngroups on graphene is revealed to be the direction of improvement\nand a key factor of response. Hence, the gas detection capacity of\nsensors with varying densities of hydroxyl groups was assessed concerning\nammonia gas, and design technology co-optimization (DTCO) is realized.\nMeasurement results show that the sensor with 70 s of hydroxylation\ntime has a 7.7% response under 22 ppm ammonia gas.