Electronic transport calculations for CO₂ adsorption on calcium-decorated graphene nanoribbons

Calcium-atom functionalization is considered to be an effective tool of enhancing CO₂ uptake capacity of carbon-based materials (Cazorla et al., 2011). Here we use density functional theory calculations combined with the nonequilibrium Green's function formalism to study electronic transport properties of Ca-decorated zig-zag and armchair graphene nanoribbons after CO₂ adsorption. Sensitivity of the system to CO₂ attachment is considerably increased due to the Ca-decoration: the electronic transmission near the Fermi level increases due to the formation of extended states. In addition, the variations of the electrostatic potential along the transport direction reduces due to CO₂ adsorption. Enhanced electronic transport due to the CO₂ adsorption is also obtained in current-voltage calculations. Since the conductivity change is one of the main properties of gas sensors, our results will be useful in developing graphene-based solid-state gas sensors.