Nanoelectrochemical Sensor Systems: Molecular Diffusion Simulations, Sensor Design, Fabrication and Characterization

Nanoelectrochemical sensors comprising of single gold nanowires or interdigitated nanowire arrays were simulated, designed and then fabricated on silicon chip substrates. Each chip comprised of six nanoscale electrodes (100 nm wide, 50 nm high and 45 μm long), on-chip counter & reference electrodes and an SD pinout. Finite element simulations, confirmed by experiment, suggested that electrolysing water, which increases H+ and OH-ions at the anode and cathode, respectively, would allow local pH control at interdigitated nanowire sensors. The interdigitated nanowire arrays also enabled generator-collector type measurements to be undertaken, providing more sensitive results and also the ability to tailor the chemistry temporally and spatially at sensor locations. SIRC behaviour was also observed when one comb of the interdigitated array was allowed to electrically float and the electrode array demonstrated enhanced sensitivity. Dissolved oxygen detection using nanowire arrays showed enhanced sensing when compared to state of the art sensors.