Design, fabrication and characterization of a miniaturized series-connected potentiometric oxygen sensor

Miniaturization of potentiometric sensors facilitates connecting many sensors in series to amplify the output. Miniaturized series-connected potentiometric sensors were developed on a silicon (Si) wafer by microfabrication techniques. The sensors consist of a thin film yttria stabilized zirconia (YSZ) electrolyte and platinum (Pt) electrodes. The reference oxygen partial pressure is determined by a nickel-nickel oxide (Ni-NiO) mixture. The open circuit voltage (OCV) was tested in air at 300 °C and was found to be lower than expected. The output of the net sensor increased almost linearly by connecting 10 sensors in series. Impedance spectroscopy was used to investigate the electrolyte and electrolyte-electrode interfaces using a two electrode configuration.