Active current gating in electrically biased conical nanopores

We observed that the ionic current through a gold/silicon nitride (Si 3 N 4 ) nanopore could be modulated and gated by electrically biasing the gold layer. Rather than employing chemical modification to alter device behavior, we achieved control of conductance directly by electrically biasing the gold portion of the nanopore. By stepping through a range of bias potentials under a constant trans-pore electric field, we observed a gating phenomenon in the trans-pore current response in a variety of solutions including potassium chloride (KCl), sodium chloride (NaCl), and potassium iodide (KI). A computational model with a conical nanopore was developed to examine the effect of the Gouy–Chapman–Stern electrical double layer along with nanopore geometry, work function potentials, and applied electrical bias on the ionic current. The numerical results indicated that the observed modulation and gating behavior was due to dynamic reorganization of the electrical double...

Samuel Bearden, Erik Simpanen and Guigen Zhang

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