Investigation of gas sensing properties of armchair graphene nanoribbons

Abstract

A theoretical approach based on a tight-binding model is developed for studying theeffects of finite concentration gas adsorption (for what are known as diatomic,triatomic and quadratomic gas molecules in the general forms denoted byXY,XY2 and XY3, respectively) on electronic properties of armchair graphene nanoribbons (AGNRs). Toconsider the edge effects on electronic properties of pure AGNRs for the firsttime, two hopping parameters, for hydrogen–carbon and carbon–carbon nearestneighbor hopping, are considered. We found, for some specified values of hoppingintegrals and random on-site energies, that adsorbed molecule AGNRs act asdonors or acceptors, which is consistent with reported experimental results for CO,NO2,O2,N2,CO2 and NH3 adsorption on graphene. Then by using these parameters and the coherent potentialapproximation, we investigated the effect of finite concentration gas molecule adsorption onthe average density of states. Our results could be used to make p-type or n-typesemiconductors by means of finite concentration adsorption of gas molecules or a gassensor.