Stacking and curvature-dependent behaviors of electronic transport and molecular adsorptions of graphene: A comparative study of bilayer graphene and carbon nanotube

Graphene is a good candidate material for high-performance sensor devices due to its excellent conductivity and large surface-to-volume ratio. Bilayer of graphene exhibits rich electronic properties owing to a variety of its stacking patterns, which may provide novel sensors. In this article, we present adsorption effects of environmental pollutants or hazardous molecules (CO, CO2, NO, and NO2) and abundant molecules (O-2 and N-2) in air on stabilities of boron (B)-doped bilayer graphenes with Bernal (AB)-stacking as well as AA- and AA'-stacking patterns based on a first-principles density-functional study. We find that only NO and NO2 molecules in air are chemically adsorbed on B-doped bilayer graphenes with AB, AA and AA' stackings. We further investigate, for the first time, electronic transport properties through pristine and B-doped bilayer graphenes with and without NO and NO2 molecules from our first-principles density-functional study. We find that electronic transport properties of AB-, AA-, and AA'-stacked bilayer graphenes exhibit specific behaviors depending on the stacking patterns and the presence of the NO/NO2 molecule. Therefore, NO and NO2 molecules should be individually detectable under low bias voltages by using B-doped bilayer graphene. In addition, we also reveal the electronic transport properties of the very thin pristine and doped carbon nanotubes (CNTs) with and without a hazardous molecule and discuss their curvature effects of the CNT. Our theoretical findings for bilayer graphenes and CNTs should provide new insight into designing graphene-based low-power sensor devices.