Low-noise single-chip potentiostat for nano-bio-electrochemistry over a 1MHz bandwidth

A single-chip versatile potentiostat is presented that allows multiple amperometric electrochemical measurements at the nanoscale. Cyclic voltammetry, impedance spectroscopy, impedance time tracking and amperometry can be performed over a 1 MHz bandwidth, with sub-pA resolution and over an unlimited measuring time. The design of the current amplifier, based on a simple transistor matching architecture, is illustrated. The results of the experimental characterization and of the validation electrochemical tests are discussed. The performances demonstrated, such as 3aF_rms capacitance resolution with an applied 100 kHz sinusoid of only 25 mV, are suitable for electrochemical investigation at sub-micrometric electrodes, in particular for biotechnology applications.