Nucleobase-Bonded Graphene Nanoribbon Junctions: Electron Transport from First Principles

Carbon and hydrogen bonding constitute the backbone of life; in the form of graphene, possibly functionalized by DNA nucleobases, these hold promise for the programmable assembly of graphene-based nanoelectronic devices. It is still unknown how hydrogen-bonded junctions inherent in such devices will perform as electron transport media. Here, we design nucleobase-bonded graphene nanoribbons and quantify their quantum transport characteristics using first-principles calculations. Pronounced rectifying behavior and negative differential resistance are found, as well as high conductance of certain structures, with the guanine-cytosine junction in general being superior to the adenine-thymine junction. The identified sensitivity of the conductance to atomic details of the interfaces offers initial hints and guidance for experimental realization. The dependence of current on electrostatic gate doping, with an on/off ratio of ∼10², shows the potential of the junction as a field effect transistor.