Solid-state nanopores can act as single-molecule sensors and could potentially be used to rapidly sequence DNA molecules. However, nanopores are typically fabricated in insulating membranes that are as thick as 15 bases, which makes it difficult for the devices to read individual bases. Graphene is only 0.335 nm thick (equivalent to the spacing between two bases in a DNA chain) and could therefore provide a suitable membrane for sequencing applications. Here, we show that a solid-state nanopore can be integrated with a graphene nanoribbon transistor to create a sensor for DNA translocation. As DNA molecules move through the pore, the device can simultaneously measure drops in ionic current and changes in local voltage in the transistor, which can both be used to detect the molecules. We examine the correlation between these two signals and use the ionic current measurements as a real-time control of the graphene-based sensing device.

The operation of four basic two-input logic gates fabricated with a single graphene transistor is demonstrated. Single-transistor operation is obtained in a circuit designed to exploit the charge neutrality point of graphene to perform Boolean logic. The type of logic function is selected by offset of the input digital signals. The merits and limitations of the fabricated gates are assessed by comparing their performance with that of conventional logic gates

The operation of a digital logic inverter consisting of one pp- and one nn-type graphene transistor integrated on the same sheet of monolayer graphene is demonstrated. Both transistors initially exhibited pp-type behavior at low gate voltages, since air contamination shifted their Dirac points from zero to a positive gate voltage. Contaminants in one transistor were removed by electrical annealing, which shifted its Dirac point back and therefore restored nn-type behavior. Boolean inversion is obtained by operating the transistors between their Dirac points. The fabricated inverter represents an important step toward the development of digital integrated circuits on graphene

In the past decade, a number of single-molecule methods have been developed with the aim of investigating single protein and nucleic acid interactions. For the first time we use solid-state nanopore sensing to detect a single E. coli RNAP−DNA transcription complex and single E. coli RNAP enzyme. On the basis of their specific conductance translocation signature, we can discriminate and identify between those two types of molecular translocations and translocations of bare DNA. This opens up a new perspectives for investigating transcription processes at the single-molecule level.