Adsorption of CO₂ on Fe-doped graphene nano-ribbons: Investigation of transport properties

Density functional theory combined with the non-equilibrium Green's function formalism is used to study the conductance response of Fe-doped graphene nano-ribbons (GNRs) to CO₂ gas adsorption. A single Fe atom is either adsorbed on GNR's surface (aFe-graphene) or it substitutes the carbon atom (sFe-graphene). Metal atom doping reduces the electronic transmission of pristine graphene due to the localization of electronic states near the impurity site. Moreover, the aFe-graphene is found to be less sensitive to the CO₂ molecule attachment as compared to the sFe-graphene system. These behaviours are not only consolidated but rather confirmed by calculating the IV characteristics from which both surface resistance and its sensitivity to the gas are estimated. Since the change in the conductivity is one of the main outputs of sensors, our findings will be useful in developing efficient graphene-based solid-state gas sensors.