Multilevel Resistive Switching in Flexible RRAM Devices with a PVP:MoSe₂ Active Layer

In this work, a unique composite of a polymer and two-dimensional material (PVP:MoSe2) is demonstrated as a potential resistive switching layer for flexible resistive random-access memory (RRAM) devices, exhibiting multilevel switching. Fabricated flexible RRAM devices exhibit forming-free and excellent resistive switching with low SET and RESET voltages (0.7 V/∼−1 V), high DC endurance of more than 1000 cycles, and an excellent retention time of 104 seconds with decent ION/IOFF (∼103). These devices exhibit multilevel resistive switching for 2-bit storage (four levels), by tuning the compliance current values, which can be the simplest way to achieve this functionality. Moreover, these devices exhibit high stability in performance upon bending, as explored up to a low bending radius of 7 mm. Our results indicate that the composites of PVP and MoSe2, a rarely explored transition metal dichalcogenide, can be a great choice as switching layer for flexible electronics. Further, this study also opens up a direction for exploration of other unique material combinations for switching layers toward application in multibit storage, as it may contribute to low-cost, high-density, and nonvolatile flexible RRAM devices.