Silicon nanopores as bioelectronic devices: A simulation study

Solid-state aqueous pores of nanoscale dimensions are now a reality, thanks to the advancing fabrication techniques. The interest in such devices has been high in the last decade, due to their potential as molecular sensing elements (Kirby and Hasselbrink in Electrophoresis 25(2):187-202, 2004) and in fast DNA sequencing (Smeets et al. in Nano Lett. 6(1), 2006). This work focuses on the theoretical characterization and numerical modeling of the role of oxidated surface electric charge in the ionic conduction process through man-made silicon nanopores. We have extended the model presented in (Behrens and Grier in J. Chem. Phys. 115(14), 2001) by including potassium adsorption on the oxidated silicon (silica) surface, as well as taking the cylindrical curvature of the surface into account. Being able to calculate the surface charge density, we have used a particle-based Brownian dynamics simulation tool to characterize the ionic population in nanopores and simulate conduction through nanopores at various bulk electrolyte concentrations.