  Bipolar nanofluidic diode is based on nanopore with positive and negative
surface charges separated by a junction. This paper investigates the effects of
the pore structure, taking the bullet-like pore as an example, on the ion
current rectification. The Poisson-Nernst-Planck Modelings show that the ion
current rectification behavior can be greatly influenced by the shape of the
pore. The bipolar nanofluidic diode with more tapered tip has significantly
higher ion current rectification degree. The modelling results indicate that
special design of the nanopore is necessary for the performance of the bipolar
nanofluidic diode.
