Electrical Conductivity of Hydrogenated Armchair Nanoribbon as a Gas Sensor by Using of Non-Equilibrium Green's Function Method

Nano sensing properties of Hydrogenated edges Armchair Grephene Nano Ribbons (HAGNR) are investigated. Using Non-equilibrium Green's Function (NGF) method in the tight binding approach, effects of hydrogen and oxygen adsorption on current-voltage (I-V) characteristics and also electrical conductivity of these systems are calculated. We found that I-V curve of these systems change by adsorption of hydrogen or oxygen molecules. Also we found conductivity of these systems at low adsorption concentrations increases while at high adsorption concentrations decrease. This could be explained in terms of semiconducting or metallic properties of the adsorbed system which is obtained from electronic properties of our clean HAGNR system. On the other hand, LDOS of some sites have a metallic behavior while the other sites have a semiconducting behavior. Note that our results are investigated at the fixed temperature of T=300K, i.e. room temperature. By calibration of conductivity in terms of adsorbed gas molecules one can make a gas nano sensor.