Since the capacitance of an oxide mixture consiting of two kinds of semiconducting oxides depends on the NO concentration, these mixed-oxide capacitors can be applied for a capacitive type of NOx sensor. Among the examined oxides, NiO mixed with ZnO was the most promising in terms of the sensitivity and response characteristics. A temperature slightly higher than 300°C was desirable as the operating temperature of the NiO-ZnO element, and a linear relationship between capacitance and NOx concentration exists below 30 ppm. Furthermore, the capacitance of NiO-ZnO is highly selective to NOx. As a result, the binary oxide of NiO-ZnO has a great potential as a new type of NOx sensor based on a capacitance change.
All Science Journal Classification (ASJC) codes
- Electronic, Optical and Magnetic Materials
- Condensed Matter Physics
- Surfaces, Coatings and Films
- Metals and Alloys
- Electrical and Electronic Engineering
- Materials Chemistry