Fig. 1: In-pore chemistry-driven voltage-gated solid-state nanopores.

a Schematic illustration depicting the working principle of a voltage-gated nanopore. It consists of a nanopore of a lithographically defined diameter in a thin SiN_x membrane, separating cis and trans compartments filled with different salt solutions. The transmembrane voltage V_b generates a flux of cationic and anionic reactants into the nanopore, inducing chemical reactions for nucleation and growth of a nanoprecipitate layer therein. The reaction process is monitored via the measurements of the ionic current I_ion. b I_ion–V_b characteristics obtained for a 100 nm-sized SiN_x nanopore with cis and trans filled with 2 M MnCl₂ and PBS, respectively (open circles: positive V_b scan; solid circles: negative V_b scan). As depicted in the insets, negative voltage brings Mn²⁺ and (PO₄)³⁻ into the pore for the precipitation of manganese phosphates, thereby suppressing the ion transport. Conversely, a positive voltage reverses the ion flux to stop the precipitation reaction. Simultaneously, the manganese phosphate dissolves into the acidic MnCl₂ solution, returning the pore to the fully opened state. c, d Stability of the in-pore reactions. I_ion–V_b curves are highly reproducible over 756 cycles of voltage scans from −1.5 V to 1.5 V in ~10 hours (c, d). The curves are presented in the form of a two-dimensional histogram, where the color coding denotes the counts of data points in each bin of size 20 nA and 0.02 V. e Rectification ratio r_rec at V_b = ±1 V in each of the 756 I_ion–V_b curves. The variation in r_rec is attributable to a change in the ion concentration due to water evaporation and residual precipitates remained undissolved on the pore wall surface during the 10 hours of measurement. Source data are provided as a Source Data file.