We present a study of hybrid graphene nanoribbon-nanopore devices for biomolecule detection and ultimately DNA sequencing. When a graphene nanoribbon(GNR) width is constricted to ~10nm, the variation of the potential created by the different bases of a DNA strand passing through an adjacent nanopore will create a sufficient variation of the ribbon conductivity to enable electrical discrimination between DNA bases. We fabricated back or side gated devices comprised of nanopores with diameters in the range of 2−10 nm at the edge or in the center of GNRs with widths between 5nm and 200 nm, on 40 nm thick silicon nitride (SiNx) membranes. We discuss the challenges encountered in the manufacturing of these nanoconstrictions (by lithography or electron beam sculpting) and the irradiation effects of the electron beam during the nanopore formation. GNR conductance is monitored in situ during the nanopore formation process inside a transmission electron microscope (TEM) operating at 200 kV for different doping levels induced by the side or back gates.
We identify and study a linear and a superlinear regime for the increase of GNR resistance with the electron dose, and correlate with the decrease by a factor of ten or more in mobility when GNRs are imaged at relatively high magnification prior to the nanopore formation. Bases on our findings we devise a scanning TEM procedure which prevent the GNR electron induced damage, enabling sensitive biosensors. We finally present the operation of this sensor for biomolecule detection and DNA sequencing, correlating the electric signal measured in the GNR to the ionic current measured through the nanopore. The higher current(~μA) which can be driven through a GNR compared to the ionic current(~nA) leads to a hundredfold increase in the measuring bandwidth(10-100MHz), possibly enabling DNA sequencing without slowing the molecules - for a projected 10 minutes full genome sequencing.
 Towards sensitive graphene nanoribbon-nanopore devices by preventing electron beam induced damage. M. Puster*, J. A. RodrÃguez- Manzo*, A. Balan*, M. Drndić. ACS Nano, in review (2013). *equal authorship
 Differentiation of short, single-stranded DNA homopolymers in solid-state nanopores. K. Venta, G. Shemer, M. Puster, J. A. RodrÃguez- Manzo, A. Balan, J. K. Rosenstein, K. Shepard, M. Drndić. ACS Nano, 7: 4629-4636 (2013).