Fig. 1: A 2D MoS₂ nanopore and nanopore instability.

a Schematic showing a single crystal of monolayer MoS₂ transferred over a SiN_x membrane (~20 nm thick). The crystalline monolayer MoS₂ is free-standing over a SiN_x aperture of ~80 nm. A suitable nanopore is then created in the suspended part. b Optical micrograph of a 2D nanopore device after transfer of a monolayer MoS₂. c The bright-field TEM image of a clean suspended MoS₂ membrane and (d) an aberration-corrected ADF-STEM image of the membrane show a perfect lattice with brighter Mo-atoms (indicated with blue circles) and relatively lighter S-atoms (indicated with yellow circles). e A nanopore (~2.5 nm) drilled in ADF-STEM mode is shown with an intensity profile highlighting the Mo-atoms with a dangling bond at the edge of the nanopore. f Representative ionic current traces of two different nanopore devices that show stable and increasing open-pore current with time, respectively, emphasize the instability in 2D nanopores. g, h Schematic showing the mechanisms of device instability issues arising during the course of a nanopore experiment. The red spheres represent oxygen atoms at the edges of the MoS₂ nanopore.