Confined Electrochemical Deposition in Sub-15 nm Space for Preparing Nanogap Electrodes

Electrode gaps with nanoscale separation offer great promise for molecular electronics and biosensing. Previous electrochemical methods to prepare nanogaps by depositing metal on pre-defined electrode tips have suffered from lack of control in the thickness direction and reproducible control of gap size. Here we report a new process wherein the electrochemical deposition is confined by a cavity to produce a nanogap with thickness smaller even than that of the initial electrodes. Using this process, we demonstrate controlled and reversible electrochemical deposition in a sub-15 nm space, to produce a nano-fluidic channel with finely tunable nanogap control electrodes for biosensing applications.