Controlled sulfidation of silver: a pathway to Ag₂S for short-term synaptic emulation

Neuromorphic computing demands scalable, energy-efficient synaptic devices, yet conventional synthesis routes impose prohibitive cost and complexity barriers. This work presents a transformative strategy for material design in which room-temperature exposure to hydrogen sulfide gas converts thermally deposited silver films into phase-pure monoclinic α-Ag₂S, a superionic conductor well-suited for electrochemical metallization (ECM) switching. Structural characterization confirms complete FCC-to-monoclinic phase transformation within 48 hours. Planar Ag/Ag₂S/Ag memristors fabricated from these films exhibit robust unipolar resistive switching with exceptional reproducibility across 16 devices. Systematic pulse-train studies reveal consistent short-term plasticity (STP) behavior, with volatile retention averaging ∼49 seconds at 100 µA compliance. This synthesis approach eliminates vacuum processing requirements, enabling the scalable production of high-performance α-Ag₂S switching layers. This positions ECM devices as accessible and practical elements for neuromorphic hardware.