(530f) Biomodular High Temperature Planar Oxygen Gas Sensor

A planar O₂ bimodular sensor was fabricated by using yttria-stabilized zirconia (YSZ) substrate and NiO thin film. The NiO films were prepared by r.f. magnetron sputtering of NiO on YSZ substrate. The surface morphology of NiO film after sintering was observed by scanning electron microscopy (SEM) and atomic force microscopy (AFM). X-ray diffraction patterns suggested that NiO was coated on YSZ surface and it was stable even after high temperature oxygen sensing. The oxygen detection experiments were performed at 500-800°C under both potentiometric mode and resistance mode. For the potentiometric mode, the linear relationship between the EMF output of the sensor and the logarithm of the O₂ concentration was observed. For the resistance mode, the sensitivity increased with temperatures as well as concentrations, and the result was in good agreement with the relationship between the semiconductor electrical conductivity and oxygen concentrations. Both detection modes showed sensitive, reproducible and reversible response to oxygen. The combination of two detection modes into one sensor could open a new venue in high temperature gas sensing field.