Active current gating in electrically biased conical nanopores

Samuel Bearden, Erik Simpanen, Guigen Zhang

Research output: Contribution to journalArticlepeer-review

10 Scopus citations

Abstract

We observed that the ionic current through a gold/silicon nitride (Si3N4) 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 layer in response to changes in the electrical bias. Specifically, in the conducting state, the nanopore conductance (both numerical and experimental) is linearly proportional to the applied bias due to accumulation of charge in the diffuse layer. The gating effect occurs due to the asymmetric charge distribution in the fluid induced by the distribution of potentials at the nanopore surface. Time dependent changes in current due to restructuring of the electrical double layer occur when the electrostatic bias is instantaneously changed. The nanopore device demonstrates direct external control over nanopore behavior via modulation of the electrical double layer by electrostatic biasing.

Original languageEnglish
Article number185502
Pages (from-to)1-11
Number of pages11
JournalNanotechnology
Volume26
Issue number18
DOIs
StatePublished - May 8 2015

Bibliographical note

Publisher Copyright:
© 2015 IOP Publishing Ltd.

Keywords

  • Biosensors
  • Electrical double layer
  • Ionic transistors
  • Nanofluidics
  • Transport

ASJC Scopus subject areas

  • Bioengineering
  • General Chemistry
  • General Materials Science
  • Mechanics of Materials
  • Mechanical Engineering
  • Electrical and Electronic Engineering

Fingerprint

Dive into the research topics of 'Active current gating in electrically biased conical nanopores'. Together they form a unique fingerprint.

Cite this