Antimony-contact MoS2 FET gas sensors for reinforcement-learning-driven hazard perception at room temperature.

Abstract

Two-dimensional van der Waals semiconductors promise low-power chemical perception at room temperature, yet contact-limited on-currents and slow recovery impede closed-loop decision making in hazardous environments. Here we propose antimony (Sb)-contact two-dimensional (2D) monolayer MoS₂ field-effect transistors (FETs) that leverage contact engineering to boost on-current and charge-transfer gas response for room temperature detection and enable electrically programmable recovery via pre-bias pulses that actively accelerate desorption and baseline restoration. The Sb-contact MoS₂ FETs show unprecedented ppb gas response (363,600% at 500 ppb NO₂) and rapid, repeatable room temperature recovery with ultra-low energy consumption (42 pJ, representing the intrinsic energy efficiency of the sensing front-end), serving as a proof-of-concept for the front-end of a safety-constrained reinforcement-learning (RL) stack that detects leak sources and plans low-risk escape path in turbulent interiors. We cast joint seek-and-escape as a single constrained Markov decision process informed by real-time transduction features fused with thermal-flow cues; the learned policy achieves earlier detection, lower cumulative exposure, and shorter safe-egress paths than heuristic baselines in computational fluid dynamics (CFD)-validated simulations and chamber trials. By uniting contact-engineered 2D transducers with risk-aware RL, this work advances room temperature chemical sensing from passive monitoring to closed-loop action.