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 (I₂) 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.