NO2 Gas Sensor Using Iodine Doped Graphene at Room Temperature With Electric Field Enhanced Recovery

A novel carbon-based material was synthesized by chemical doping of Iodine (I-2) into multilayer graphene (MLG) using photolysis method. Elemental analysis using Energy Dispersive X-ray (EDX) determined low amount of Iodine doping in the graphene. Raman spectroscopy demonstrated increase in number of layers of graphene. Iodine doped graphene (I-MLG) showed a sharp reduction in resistance when exposed to NO2 gas at room temperature. It demonstrated sensing response of 69% for 100 ppm of gas in just 16 seconds at room temperature. When compared with other gases and vapours, I-MLG showed selective sensing towards NO2 gas by reduction in resistance during exposure. Hybrid Material displayed reversible sensing but recovery after the removal of NO2 gas source took 1380 seconds. An electric field assisting sensor element was fabricated to lower the recovery time to 156 seconds after applying negative gate voltage of -15V. Sensing and recovery mechanisms of I-MLG along with effect of electric field are presented.