Electron-tunneling modulation in percolating network of graphene quantum dots: fabrication, phenomenological understanding, and humidity/pressure sensing applications.

The two-dimensional (2D) electron cloud, flexible carbon-carbon bonds, chemical modifiability, and size-dependent quantum-confinement and capacitance makes graphene nanostructures (GN) a widely tunable material for electronics. Here we report the oxidation-led edge-roughening and cleavage of long graphene nanoribbons (GNRs) (150 nm wide) synthesized via nanotomy (nanoscale cutting) of graphite (with 2 nm edged diamond knife) to produce graphene quantum dots (GQD). These GQDs (~100-200 nm) selectively interfaced with polyelectrolyte microfiber (diameter = 2-20 μm) form an electrically percolating-network exhibiting a characteristic Coulomb blockade signature with a dry tunneling distance of 0.