An ab initio study on energy gap of bilayer graphene nanoribbons with armchair edges

Dependency of energy bandgap (E-g) of bilayer armchair graphene nanoribbons (AGNR(B)) on their widths, interlayer distance (D), and edge doping concentration of boron/nitrogen was investigated using local density approximation and compare to the results of monolayer graphene nanoribbons (AGNR(M)). Although E-g of AGNR(B), in general, is smaller than that of AGNR(M), of AGNR(B) exhibits two distinct groups, metal and semiconductor, while AGNR(M) displays purely semiconducting behavior. Moreover, E-g of AGNR(B) is highly sensitive to D, indicating a possible application in tuning E-g by varying D. Finally, edge doping of both AGNR systems reduces E-g by 11%-17%/4%-10% for AGNR(M)/AGNR(B), respectively. (c) 2008 American Institute of Physics.