Scope of ZnO based gas sensors for sensing CO emission from vehicle tailpipe-A Short Review

Vehicle exhaust gas contains a significant amount of CO gas, which is extremely harmful to human health and the environment. For CO gas emission monitoring, a low-cost sensor would be an excellent choice. Low-cost sensors, on the other hand, have challenges in their characteristics such as robustness, measurement repeatability, and accuracy. This review investigates the fabrication of ZnO based thin film CO gas sensors and their applications for detecting detrimental CO gas emissions. The fabrication of ZnO thin film CO gas sensor using DC and RF sputtering methods is discussed in this paper. The role of doping to improve sensor’s performance is also discussed in this study. Conventional ZnO-based CO gas sensors are targetted to operate at room/low temperature. However, the CO gas sensing from the tailpipe requires a high operating temperature. Furthermore, this paper highlights current developments in the fabrication of ZnO thin film gas sensors, as well as the possibility of future research for further improvement.