Realizing the Ultrafast Recovery of the Monolayer MoS₂-Based NH₃ Sensor by Gas-Ion-Gate

Over the past decade, the two-dimensional material MoS₂ has attracted great attention due to its room temperature stability, high surface area-to-volume ratios, abundance of active sites at the edges, and exceptional surface sensitivity to the environment, which are key characteristics for applications in chemical sensing. However, the slow recovery of ammonia (NH₃) sensors based on MoS₂ materials at room temperature has restricted their further development. This paper presents a novel approach to address this limitation by demonstrating a monolayer MoS₂-based NH₃ sensor with rapid recovery capabilities, leveraging O₂^- generated through gas-ion-gate (GIG) technology. After being modulated by GIG, the recovery time of the monolayer MoS₂ device is about 2.04 s, representing a substantial improvement─approximately 157 times faster than that without GIG modulation. The rapid recovery speed is attributed to the chemical interactions between the O₂^- ions generated by GIG and the surface-adsorbed NH₃⁺, which expedite the rapid desorption of NH₃⁺. Furthermore, the device retains periodic recovery properties, even after multiple modulation cycles, indicating that the material remains undamaged. This method successfully resolves the critical issue of slow recovery in monolayer MoS₂-based NH₃ sensors at room temperature.