Miniaturised MOX based sensors for pollutant and explosive gases detection

- A miniaturised metal oxides based sensor for explosive gases detection was developed.
- Electro-thermal analyses were performed, with the purpose to optimize the sensor's heating element.
- Different sol gel metal oxides layers were used to validate the sensor's response to low values of CO, CH4 and C3H8.

The research proposes to obtain an optimized gas sensing system for monitoring very low concentration of pollutant and explosive gases to in domestic or industrial environments. The design, simulation, sensors fabrication and testing results are provided. The microsensors on nanostructured metal oxides (SnO2, ZnO, SnO2:ZnO, SnO2:ZnO:Fe2O3) have been fabricated and tested for CO, C3H8 and CH4 detection. Miniaturized IDT (interdigitated transducer) electrodes made on Ti(50 nm)/Au(150 nm), patterned on the front side of a 0.2 mm thick alumina wafer have been fabricated. Sensitive coating consisting of different nanostructured metal oxides was deposited on the ITD's, together with a Ti/Pt heater patterned on the back side of the alumina wafer. Working temperatures between 250 °C ÷ 550 °C can be reached by applying 15 V DC for 5-20 s. The chosen fabrication technology provides a reliable and low-cost sensing device.