Ionic Field Effect Transistors with Sub-10 nm Multiple Nanopores

Abstract

We report a new method to fabricate electrode-embedded multiple nanopore structures with sub-10 nm diameter, which is designed for electrofluidic applications such as ionic field effect transistors. Our method involves patterning pore structures on membranes using e-beam lithography and shrinking the pore diameter by a self-limiting atomic layer deposition process. We demonstrate that 70-80 nm diameter pores can be shrunk down to sub-10 nm diameter and that the ionic transport of KCl electrolyte can be efficiently manipulated by the embedded electrode within the membrane.

Experimental Verification of Overlimiting Current by Surface Conduction and Electro-Osmotic Flow in Microchannels

“…Noticeable progress has been made in understanding electroconvection during ion concentration polarization (ICP) due to electro-osmotic flows near the membrane or nanochannel interface driving salt depletion [5,[7][8][9][10]. Due to the complexity of direct numerical simulation of the Poisson equation (for electric potential), Nernst-Planck equations (for ion concentrations), and Navier-Stokes equations (for fluid flows) in multidimensional geometries [9,11,12], as well as inherent limitations of the classical dilute solution model [13], it is crucial to directly observe particle motions and flow fields in precisely controlled micro-or nanofluidic geometries [14,15].…”

Toward Complementary Ionic Circuits: The npn Ion Bipolar Junction Transistor

“…Ideally, these ionic transistors should have a high ratio between the on and off current to minimize leakage, a fast switching speed, a high current gain, be possible to integrate into a larger system and they should also be functional at physiological conditions. Recently, nanofluidic transistors and diodes have received a lot of attention [4][5][6] . In these devices the surface charge along the walls of the thin channels modulates the conductivity through the device.…”

Carbon nanotube-based nano-fluidic devices

“…The ion current is only partially gated, as is characteristic of ionic FETs, 16,17,85 the ionic conductance falling to a lower limit, G + , at the highest positive gate bias (G + is shown for a single value of V ionic in Figure 5.2b). The fraction of conductance that can be switched is characterized G/G + (where G = G --G + , see Figure 5.2b).…”