Field-effect reconfigurable nanofluidic ionic diodes.

Several types of nanofluidic devices based on nanopores and nanochannels have been reported to yield ionic current rectification, with the aim to control the delivery of chemical species in integrated systems. However, the rectifying properties obtained by existing approaches cannot be altered once the devices are made. It would be desirable to have the ability to modulate the predefined properties in situ without introducing external chemical stimuli. Here we report a field-effect reconfigurable nanofluidic diode, with a single asymmetrically placed gate or dual split-gate on top of the nanochannel. The forward/reverse directions of the diode as well as the degrees of rectification can be regulated by the application of gate voltages. Compared with the stimuli-responsive tuning of the rectification properties, the electrostatic modulation offers a fully independent and digitally programmable approach for controlling the preferential conduction of ions and molecules in fluids. This device would serve as a building block for large-scale integration of reconfigurable ionic circuits.