Real-time visualization and sub-diffraction limit localization of nanometer-scale pore formation by dielectric breakdown.

Herein, we introduce synchronous, real-time, electro-optical monitoring of nanopore formation by DB. Using the same principle as sub-diffraction microscopy, our nanopore localization platform based on wide-field microscopy and calcium indicators provides nanoscale sensitivity. This enables us to establish critical limitations of the fabrication process and improve its reliability. In particular, we find that under certain conditions, multiple nanopores may form and that nanopores may preferentially localize at the membrane junction, either of which potentially render nanopore sensing ineffective. As the breakdown parameters of silicon materials are highly manufacturer-specific, we anticipate that our visualization platform will enable users to easily optimize DB fabrication according to specific needs. Furthermore, our technique furthers the applicability of DB to more complicated architectures, such as membranes with selectively thinned regions and plasmonic nanowells.