Realizing Scalable Two-Dimensional MoS2 Synaptic Devices for Neuromorphic Computing

Atomically thin two-dimensional transition metal dichalcogenides (2D TMDs) are of interest for neuromorphic computing due to their extraordinary properties such as low power consumption, robustness, flexibility, and layered anisotropic transport properties. Here, we present metal-ion assisted 2D MoS2 neuromorphic devices fabricated using a simple sputtering method. This method enables us to synthesize large-scale and uniform nanostructured polycrystalline MoS2 films on flexible substrates. We found that the small grain of the MoS2 film effectively enhances the ion transport through the grain boundaries or interfaces in the MoS2 film, which results in excellent neuromorphic characteristics such as bipolar electrical property, short-/Iong-term plasticity (STP/LTP) with a high ratio of I-LRS/I-HRS (similar to 10(5)), paired-pulse facilitation (PPF), and stability. Furthermore, it was found that the memory performance parameters such as the SET/RESET voltage (V-SET/V-RESET) and the programming/erasing current ratio (I-on/I-off) can be affected by the concentration of ions inserted into MoS2. This work provides insight for realizing practical neuromorphic devices and understanding ion-mediated synaptic behavior of nanocrystal structures, which can be tuned for high-efficiency neuromorphic devices.