Speaker
Description
In our contemporary, heavily industrialized world, there is a growing demand for innovation in gas monitoring technologies capable of selectively and accurately detecting various toxic analytes. Metal oxide-based chemoresistive sensors have garnered significant interest due to their high sensitivity, cost-effectiveness, and easy device integration. In this study, we aim to develop a sensing platform capable of a selective response toward hydrogen sulphide (H2S), a highly toxic and flammable compound. The active material selected for this research is ceria (CeO2), a rare-earth metal oxide deposited via a large-area Pulsed Laser Deposition system onto a 4-inch Si wafer. The characterizations of the obtained thin films include crystallographic analysis via X-ray diffraction, thickness and optical bandgap measurements through ellipsometry, and surface morphology evaluation using Scanning Electron Microscopy. Subsequently, the samples underwent gas sensing tests. The performance was evaluated at operating temperatures ranging from 25°C to 400°C. Dynamic response curves were also recorded to establish the response and recovery time of the CeO2-based devices. To evaluate the selectivity of the chemoresistive sensor, tests were performed against a wide array of gases, including synthetic air, O2, and COx. Initial measurements revealed limited selectivity, a common issue when it comes to chemorezistive sensors. Therefore, we functionalized the sensor surface through drop-casting. Two distinct types of nanoparticles, SnO2 and α-Fe2O3, were deposited on the surface. We look to present preliminary results demonstrating how modifications to surface morphology, electric sensitization and the catalytic behaviour of these nanostructures impact the overall performance of CeO2 chemorezistive sensors.