Nanofluidic diodes based on nanotube heterojunctions.

The mechanism of tuning charge transport in electronic devices has recently been implemented into the nanofluidic field for the active control of ion transport in nanoscale channels/pores. Here we report the first synthesis of longitudinal heterostructured SiO(2)/Al(2)O(3) nanotubes. The ionic transport through these nanotube heterojunctions exhibits clear current rectification, a signature of ionic diode behavior. Such nanofluidic diodes could find applications in ion separation and energy conversion.