Quantifying the growth mechanism of solid-state nanopores under high-voltage conditioning

Solid-state nanopores exhibit dynamically variable sizes influenced by buffer conditions and applied electric field. While dynamical pore behavior can complicate biomolecular sensing, it also offers opportunities for controlled, <i>in situ</i> modification of pore size post-fabrication. In order to optimally harness solid-state pore dynamics for controlled growth, there is a need to systematically quantify pore growth dynamics and ideally develop quantitative models to describe pore growth. Using high-voltage pulse conditioning, we investigate the expansion of nanopores and track their growth over time. Our findings reveal that pore growth follows a two-regime model: an initial transient regime characterized by an exponential rise, followed by a steady-state regime with linear growth. The pore growth rate increases with voltage, while the duration of the transition regime decreases with voltage. We propose a simple electrochemical etching model based on hydrolysis and solute removal to quantify time-dynamics of growing pores and rationalize the mechanism of electric-field driven pore growth, with numerical solutions aligning closely with experimental data. These insights enhance the understanding of nanopore conditioning, providing a theoretical framework for controlled pore size modification.