Hydrothermally synthesized and exfoliated WS ₂ –PEO nanocomposite based non-volatile resistive devices for energy-efficient neuromorphic applications

This work presents a facile, scalable nanocomposite-based resistive memory device incorporating a 2D hybrid of hydrothermally synthesized and exfoliated tungsten disulfide (E-WS₂) nanosheets embedded in a poly (ethylene oxide) (PEO) matrix for energy efficient neuromorphic applications. WS₂was synthesized via a simple, cost-effective hydrothermal method and subsequently exfoliated via liquid phase exfoliation to obtain few-layer nanosheets with improved surface uniformity and reduced defect density. These nanosheets were integrated into the active layer of an ITO/E-WS₂+ PEO/Cu device fabricated via spin coating and thermal evaporation. The device exhibits reliable bipolar resistive switching with low SET voltages, a high ON/OFF current ratio (∼10⁴), excellent retention (>450 s), and endurance over 70 cycles. The transport mechanism is governed by Ohmic conduction at low voltages, followed by space charge limited current (SCLC) and trap-controlled SCLC (TC-SCLC) mechanisms near-threshold voltages. Energy band analysis indicates that charge trapping and de-trapping at the WS₂/PEO interface plays a critical role in the switching process. Compared to bulk WS₂, exfoliated WS₂offers enhanced interfacial contact, lower resistance pathways, and reduced variability in switching, resulting in improved device performance and stability. It also shows more analog like behavior. Sulfur vacancies in E-WS₂ assist in forming conductive filaments, while the PEO matrix enhances ionic mobility and switching behavior. This work offers a scalable, environmentally benign approach to fabricating 2D material-based resistive memory, establishing solution-processed E-WS₂ nanocomposites as strong candidates for next-generation, scalable, energy-efficient non-volatile memory and neuromorphic technologies.