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 (O₂ and N₂) 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.