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Helium Scanning Transmission Ion Microscopy and Electrical Characterization of Glass Nanocapillaries with Reproducible Tip Geometries.
Journal article

Helium Scanning Transmission Ion Microscopy and Electrical Characterization of Glass Nanocapillaries with Reproducible Tip Geometries.

  • Zweifel LP Biozentrum and the Swiss Nanoscience Institute, University of Basel , 4056 Basel, Switzerland.
  • Shorubalko I Laboratory for Reliability Science and Technology, EMPA, Swiss Federal Laboratories for Materials Science and Technology , 8600 Dübendorf, Switzerland.
  • Lim RY Biozentrum and the Swiss Nanoscience Institute, University of Basel , 4056 Basel, Switzerland.
  • 2016-01-20
Published in:
  • ACS nano. - 2016
glass micropipette
helium ion microscope
ion current rectification
nanopore geometry
plasma cleaning
protein translocation
single-molecule detection
English Nanopores fabricated from glass microcapillaries are used in applications ranging from scanning ion conductance microscopy to single-molecule detection. Still, evaluating the nanocapillary tip by a noninvasive means remains challenging. For instance, electron microscopy characterization techniques can charge, heat, and contaminate the glass surface and typically require conductive coatings that influence the final tip geometry. Per contra, electrical characterization by the means of ion current through the capillary lumen provides only indirect geometrical details of the tips. Here, we show that helium scanning transmission ion microscopy provides a nondestructive and precise determination of glass nanocapillary tip geometries. This enables the reproducible fabrication of axially asymmetric blunt, bullet, and hourglass-shaped tips with opening diameters from 20 to 400 nm by laser-assisted pulling. Accordingly, this allows for an evaluation of how tip shape, pore diameter, and opening angle impact ionic current rectification behavior and the translocation of single molecules. Our analysis shows that current drops and translocation dwell times are dominated by the pore diameter and opening angles regardless of nanocapillary tip shape.
Language
  • English
Open access status
closed
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Persistent URL
https://folia.unifr.ch/global/documents/64163
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