Comprehensive Investigation of Shelf Life and Performance of Flexible Hybrid RRAM Devices With PVK:MoS2/TiO2 Bilayer

A comprehensive investigation of long-term environmental stability and performance of flexible hybrid resistive random access memory (RRAM) devices with PVK:MoS $_{\text{2}}$ /TiO $_{\text{2}}$ bilayer is presented. These devices were systematically characterized for their switching behavior for a very long duration of 20 months, and it was found that devices were able to maintain their switching behavior with maximum average $\textit{V}_{\text{SET}}$ of $\sim$ 1.5 V and lowest average $\textit{V}_{\text{RESET}}$ of $\sim$ $-$ 1.8 V, indicating high shelf life and low-voltage operation. Excellent retention of 10 $^{\text{4}}$ s was exhibited by devices even after being in ambient environment for 20 months. Although the devices exhibited almost unchanged $\textit{V}_{\text{SET}}$ and $\textit{V}_{\text{RESET}}$ values upon variation of humidity exposure (RH $\sim$ 42% to $\sim$ 99%), an increase in the magnitude of both was observed upon temperature variation from room temperature (RT) to 100 $^{\circ}$ C. A typical decay in $\textit{I}_{\text{ON}}$ / $\textit{I}_{\text{OFF}}$ by more than an order of magnitude (from $\sim$ 10 $^{\text{3}}\text{)}$ was observed upon aging and application of temperature; however, an increase in the same was observed upon exposure to high humidity on the order of 10 $^{\text{2}}$ –10 $^{\text{3}}$ . Our investigation indicates that (PVK:MoS $_{\text{2}}$ /TiO $_{\text{2}}\text{)}$ hybrid switching layer can be suitable for environmentally stable nonvolatile memory devices for flexible electronics.