WS 2 /Graphene Heterostructures by Electrochemical Deposition for Photodetectors and Memristors

Two-dimensional (2D) vertical heterostructures have garnered significant interest in electronics and optoelectronics. However, the limited growth window and constrained dimensions of these structures have presented significant obstacles to their practical application. In this study, we have successfully engineered large-area WS 2 /graphene vertical heterostructures through a highly controllable electrochemical deposition (ECD) method applied to chemical vapor deposition (CVD) graphene films. This technique empowers us to attain unprecedented control over the nanometer-scale thickness of these heterojunctions, ensuring remarkable repeatability in fabrication. Our research unveiled two compelling applications based on thickness variations: within the 4–40 nm range, these heterostructures excel as high-performance photodetectors with a photoresponsivity of up to 2.62 A/W. Detailed electronic property analysis, including Schottky barrier (ϕ SB = 310 mV) and built-in potential (ϕ Bi = 270 mV), aligns closely with theoretical predictions. Conversely, heterostructures in the 100–150 nm range excel in constructing memristor arrays with an endurance of up to 10 6 cycles, while maintaining state stability for over 10 h. Furthermore, our observations of gradual potentiation and depression processes hold great promise for advancements in neuromorphic computing and memory applications. This research signifies a significant leap in WS 2 /graphene heterostructure fabrication, enabling precision and opening horizons in electronics and optoelectronics.