Controlling the structure and composition of SnO₂-based thin film with reactive sputtering to improve the sensitivity of semiconductor CO₂ sensor

Abstract

To enhance the sensitivity of SnO2 thin film-based CO2 gas sensors by controlling the surface structure, reactive sputtering was employed during the deposition process, carefully adjusting the oxygen partial pressure to modify the surface structure of the SnO2 films. This process increased the sensitivity, primarily due to larger surface area and improved gas adsorption capabilities. Furthermore, the impact of heterojunctions between p-type SnO and n-type SnO2 on the sensitivity was investigated using a model diagram. Both theoretical analysis and experimental data consistently demonstrated that the number of heterojunction interfaces contributes significantly to the sensitivity of SnO-SnO2 heterojunction gas sensors. These findings underscore the effectiveness of controlling the surface structure and composition ratio of thin films through reactive sputtering to enhance sensitivity. This study offers valuable insights for optimizing SnO2 thin-film-based gas sensors for CO2 detection.