Fabrication and electrical characterization of a pore–cavity–pore device

Abstract

We present a solid state nanopore device structure comprising two nanopores which are stacked above each other and connected via a pyramidal cavity of 10 fl volume. The process of fabrication of the pore-cavity-pore device (PCP) relies on the formation of one pore in a Si(3)N(4) membrane by electron beam lithography, while the other pore is chemically etched into the Si carrier by a feedback controlled process. The dimensions of the two nanopores as well as the cavity can be adjusted independently, which is confirmed by transmission electron microscopy. The PCP device is characterized with respect to its electrical properties, including noise analysis and impedance spectroscopy. An equivalent circuit model is identified and resistance, capacitance, and dielectric loss factors are obtained. Potential and electric field distributions inside the electrically biased device are simulated by finite element methods. The low noise characteristics of the PCP device (comparable to a single solid state nanopore) make it suitable for the stochastic sensing of single molecules; moreover, the pore-cavity-pore architecture allows for novel kinds of experiments including the trapping of single nano-objects and single molecule time-of-flight measurements.

Entropic cages for trapping DNA near a nanopore

“…1b shows transmission electron microscope (TEM) images of a typical one. The structure is similar to the pore-cavity-pore device developed by Pedone et al 24 , but it features a cylindrical cavity as opposed to a pyramidal one. Furthermore, we judge our fabrication method to be simpler while granting us better control over the device dimensions.…”

“…Rant et al 24 took an important step towards that goal when they developed devices comprising two pores and a microscale cavity. They demonstrated that the diffusion of particles and DNA can be significantly slowed inside the cavity 25 .…”

A Colloidal Nanopatterning and Downscaling of a Highly Periodic Au Nanoporous EGFET Biosensor

“…6 The latter causes the smaller pores to encounter strictly and tightly flowing electrical double layer on each side of the pore wall which initiates ion movement blockings inside the pore, high resistance in the system leading to signal amplification, 39,40 and low translocation velocity due to intense interaction between DNA and nanoporous surface. 19,20,41 Following up the optimum analytical performance of Au nanoporous EGFET made by 100 nm PS template and 40 nm thick Au film, this substrate was subsequently used for specificity test. The specificity principle may in the future be applied to realizing a multianalyte Au nanoporous biosensor.…”

“…19,20 Not only that, in biomolecular detection, the potency of metallic nanopores includes an externally controllable electric potential owing to their ability to change flow direction by reversing the polarity of the potential difference between the pore and buffer solution.…”

“…[14][15][16] Numbers of research have also pointed out several critical parameters influencing DNA attachment toward Au nanopores including the electrophoretic forces as a results on an applied bias voltage across the membrane 17,18 and slow translocation speed indicating a massive interaction between DNA and nanoporous surface. 19,20 Not only that, in biomolecular detection, the potency of metallic nanopores includes an externally controllable electric potential owing to their ability to change flow direction by reversing the polarity of the potential difference between the pore and buffer solution. 21 Among expensive and complex nanostructuring and downscaling techniques including conventional lithography, electroplating, H3171 electron beam lithography (EBL) and the like, nanosphere lithography (NSL) has emanated as a simple and cheap colloid based lithography, particularly for the generation of highly periodic 2D metallic nanoparticles array on a large surface with 200-1000 nm range.…”