Enhancement in hazardous gas detection capabilities of MoS2 monolayer-based devices through defect engineering and photonic activation
Pukhraj Prajapat, Anis Ahmad Chaudhary, Aditya Yadav, Vaibhav Kandwal, Pargam Vashishtha, Mohamed A. M. Ali, Sumeet Walia, Govind Gupta
Abstract
The gas-sensing potential of transition metal dichalcogenides (TMDs) drew attention owing to their high surface sensitivity and tunable optoelectronic features. Among the TMDs, monolayer MoS 2 stands out as a promising material for advanced gas sensors. However, TMDs-based gas sensors still require considerable improvement in room temperature sensitivity, response times, and stability, which may be achievable through alterations in kinetics. Herein, we report a highly sensitive NH 3 gas sensor based on monolayer MoS 2 , whose sensing performance is greatly enhanced by defect engineering and photonic activation. Intestinally induced sulfur vacancies create chemically active adsorption sites, increasing adsorption energy and enhancing charge transfer between NH 3 molecules and MoS 2 . On the other hand, visible-light illumination stimulates photoresponsivity by generating electron-hole pairs to speed up desorption and recovery time. With these combined stimuli, very large modulations to the electronic band structure occur, thus enhancing the gas-surface interaction dynamics and hence sensing performance. Thus, this study highlights the potential of defect-engineered and photonic-activated monolayer MoS 2 as a strong candidate for advanced gas detection and presents a scalable pathway for next-generation sensor development, meeting the demands of environmental and industrial monitoring.