Memristive devices are promising for next-geneartion nonvolatile memory and neurmorphic computing. Their resistive switching (RS) behavior enables information storage and analog conductance modulation in compact device structures [1,2]. Two-dimensional (2D) materials such as molybdenum disulfide (MoS₂) provide an attractive switching medium for filamentary RS. Their layered structure, van der Waals (vdW) interface, structural anisotropy, and defects can strongly affect ion migration and conductive filament (CF) formation and rupture [3,4]. Here, we discuss recent progress in MoS₂-based filamentary memristive devices, spanning lateral and vertical architectures to wafer-scale fabrication and nanoscale complementary metal-oxide-semiconductor (CMOS)-integratgion.

In lateral silver (Ag)/MoS₂/palladium (Pd) devices based on metal-organic chemical vapor deposition (MOCVD)-grown multilayer MoS₂, forming-free volatile RS was achieved in structures with sub-2µm electrode gaps. The switching is driven by Ag ion migration and occurs at low voltages of ~2 V, with switching times down to 130 ns. A physics-based compact model, supported by density functional theory, connects ion migration with electron transport. This model enables circuit-level simulation of artificial-neuron behavior [5]. In related to sub-µm lateral devices, volatile and nonvolatile switching were obtained in the same MoS₂ device by adjusting the current compliance (cc). These devices showed ON/OFF ratios above 10⁴ and synaptic functions including short- and long-term plasticity [6]. Operando transmission electron microscopy (TEM) of lateral Ag/MoS₂/Pd devices further confirmed the filamentary switching mechanism. It directly visualized Ag CF formation and dissolution along MoS₂ surface, bundles, and vdW gaps under bias [7].

The device studies were then extended to vertical devices with SiO_x/vertically aligned MoS₂ (VAMoS₂) heterostructures. VAMoS₂ was synthesized by sulfurizing Mo thin films in a CVD system, controlling the MoS₂ orientations from lateral to vertical. In this vertical stack, the vdW gaps in VAMoS₂ act as preferential ion-migration pathways between the top and bottom electrodes. These heterostructure devices exhibited low-voltage threshold switching near 0.6 V, fast switching times of ~310 ns, and endurance beyond 10⁴ cycles. TEM analysis revealed residual Ag traces in the high-resistance state after cycling, while a physic-based dynamical model helped clarify the switching kinetics [8]. The SiO_x/VAMoS₂ devices showed reduced cycle-to-cycle variability compared with SiO_x-only reference devices. This improvement indicates that vertically aligned vdW gaps can guide confined filament formation and enhance switching reliability [9], as further supported by variability-aware modeling [10].

For scalability, wafer-scale vertical memristors based on MOCVD-grown multilayer MoS₂ were demonstrated. These devices showed cc-dependent Ag filament evolution, where vertical and lateral filament growth produced intermediate resistance states useful for analog synaptic weight modulation and microsecond-scale current response [11]. Finally, nanoscale MoS₂ memristors were integrated into the back-end-of-line of silicon CMOS microchips in a one-transistor-one-resistor architecture. With an active area of approximately 0.015 um², the cells exhibited forming-free nonvolatile switching at ~0.23 V for SET and ~-0.1 V for RESET. They also showed reproducible operation and low cycle-to-cycle variability. TEM confirmed Ag-based CF formation in the MoS₂ switching layer [12].

Overall, these studies show that combining switching-mechanism analysis, material-structure design, wafer-scale processing, and CMOS integration can advance MoS₂-based filamentary memristors toward scalable and energy-efficient 2D memory and neuromorphic hardware.