Threshold switching in vertically aligned MoS2/SiOx heterostructures based on silver ion migration

Abstract Threshold switching (TS) is a non-permanent change in electrical resistance controlled by voltage modulation in two-terminal devices. Silver (Ag) filament-based TS has been observed in two-dimensional transition metal dichalcogenides, which are promising due to their van der Waals gaps, facilitating ion migration and filament formation without disturbing covalent bonds. This work demonstrates the heterostructure growth of vertically aligned molybdenum disulfide (VAMoS 2 ) with an amorphous silicon oxide (SiO x ) layer after sulfurization. Ag ion migration through this material stack enables TS. Our Ag/SiO x /VAMoS 2 /Au devices exhibit low switching voltages of ~0.63 V, high on-state currents over 200 μA, and stable switching exceeding 10⁴ cycles. A physics-based dynamical model identifies two rate-limiting steps for filament formation, and the simulated switching kinetics align with experimental results. Our devices achieve fast switching in 311 ns and spontaneous relaxation in 233 ns. These findings advance understanding of switching mechanisms and highlight their potential for memory and neuromorphic computing applications.