Nonvolatile Resistive Switching in Nanocrystalline Molybdenum Disulfide with Ion-Based Plasticity

Non-volatile resistive switching is demonstrated in memristors with nanocrystalline molybdenum disulfide (MoS2) as the active material. The vertical heterostructures consist of silicon (Si), vertically aligned MoS2, and chrome/gold metal electrodes. Electrical characterizations reveal a bipolar and forming-free switching process with stable retention for at least 2500 s. Controlled experiments carried out in ambient and vacuum conditions suggest that the observed resistive switching is based on hydroxyl ions (OH-). These originate from catalytic splitting of adsorbed water molecules by MoS2. Experimental results in combination with analytical simulations further suggest that electric field driven movement of the mobile OH- ions along the vertical MoS2 layers influences the energy barrier at the Si/MoS2 interface. The scalable and semiconductor production compatible device fabrication process used in this work offers the opportunity to integrate such memristors into existing Si technology for future neuromorphic applications. The observed ion-based plasticity may be exploited in ionic-electronic devices based on transition metal dichalcogenides and other 2D materials for memristive applications.