Graphene/hexagonal boron nitride/graphene nanopore for electrical detection of single molecules

Abstract

Graphene nanopore device, since its proposal, has witnessed tremendous progress toward the goal of single-molecule detection. However, one central challenge of preparing electrodes with nanometer precision on the graphene remains unsolved. Here we show theoretically the feasibility of graphene/hexagonal BN (h-BN)/graphene structure where top graphene layer acts as one electrical contact while the bottom layer as the other. Based on quantum chemistry/nonequilibrium Green's function investigation, we give clear physical pictures why ABC stacking of the above heterogeneous layers results in excellent insulating of the top and bottom graphene electrodes. On the other hand, when the target molecule is inside the nanopore the background conductance through the h-BN dielectric will not keep decreasing even though more layers of h-BN are inside the nanopore. The mechanism is illustrated as that the presence of the molecule will enhance the vertical transmission through the h-BN dielectric via quantum interference. We employ a single-level molecule model, and show quantitatively that the discussed effect can be utilized as a powerful signal amplifier for the molecule conductance, thus enhancing the measurability of single molecules by 3-4 orders.

Single molecule detection with graphene and other two-dimensional materials: nanopores and beyond

“…Using the insulating few- (mono-) layer hexagonal boron nitride (h-BN) in-between graphene layers reduces the interlayer conductance. 49 It is postulated that in the presence of the molecule in the nanopore, the transmitted current through the two possible paths (i) via the molecules, and (ii) via the h-BN layer, may show quantum interference which could further improve the sensitivity of the device. 49 The relative orientation (stacking) of the graphene/h-BN/graphene crystals affects the electrical isolation of the graphene layers.…”

Theoretical assessment of feasibility to sequence DNA through interlayer electronic tunneling transport at aligned nanopores in bilayer graphene

“…The pore edges were passivated by OH-groups which might be a realistic scenario for wet-lab experiments 35 36 . In this way, He et al 37 recently explored the feasibility of a graphene/hexagonal boron nitride (h-BN)/graphene nanopore setup for single molecule detection. Using a precision transfer technique, Chae et al 38 have fabricated separate contacts on each layer of two stacked graphene monolayers and measured its interlayer conductance.…”

Threading DNA through nanopores for biosensing applications

“…An electrical isolation is provided by oxide barriers between the different graphene layers. Along the same lines, novel heterostructures made by alternating graphene and boron nitride films [92][93][94] or graphene and MoS 2 heterostructures [95,96] manifest tunable electronic properties which would be desirable in the field of nanopore sequencing.…”