Quantitative Correlation for Recoverable Monolayer MoS₂ Gas Sensing Mechanism: A Fundamental Approach

Gas sensing research based on transition metal dichalcogenides (TMDs) suffers from irrecoverable responses. Prior attempts to improve the recoverability, such as applying heat to the material or using heterostructure designs, pose risks of damaging the surface or increasing sensor size. The ability to achieve repeatability is of the utmost importance in gas sensing research. In this study, we propose a novel approach that leverages the surface molecule trapping characteristic of TMDs to investigate gas adsorption on the material surface, which enables the repeatability of gas sensors. Our method involves regulating the gas sensing material surface by applying high concentrations of the target adsorbent to fill inactive sites on the material surface. To validate the effectiveness of our method, we introduced a two-trap model that combines physical and chemical adsorption. We applied various concentrations of the target adsorbent in different sequences, resulting in a highly linear relationship and repeatable outcomes. Our results demonstrate that there is a consistent relationship between the response and the target adsorbent, providing evidence that our method is capable of achieving repeatability for gas sensors. Therefore, our proposed method offers a promising solution to the challenge of irrecoverable responses and emphasizes the crucial importance of repeatability in the development of gas sensing technologies.