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:MoS2/TiO2 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 <inline-formula> <tex-math notation="LaTeX">${V}_{\text {SET}}$ </tex-math></inline-formula> of ~1.5 V and lowest average <inline-formula> <tex-math notation="LaTeX">${V}_{\text {RESET}}$ </tex-math></inline-formula> of ~ −1.8 V, indicating high shelf life and low-voltage operation. Excellent retention of 104s was exhibited by devices even after being in ambient environment for 20 months. Although the devices exhibited almost unchanged <inline-formula> <tex-math notation="LaTeX">${V}_{\text {SET}}$ </tex-math></inline-formula> and <inline-formula> <tex-math notation="LaTeX">${V}_{\text {RESET}}$ </tex-math></inline-formula> values upon variation of humidity exposure (RH ~42% to ~99%), an increase in the magnitude of both was observed upon temperature variation from room temperature (RT) to 100 °C. A typical decay in <inline-formula> <tex-math notation="LaTeX">${I}_{\text {ON}}/{I}_{\text {OFF}}$ </tex-math></inline-formula> by more than an order of magnitude (from ~103) 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 102–103. Our investigation indicates that (PVK:MoS2/TiO2) hybrid switching layer can be suitable for environmentally stable nonvolatile memory devices for flexible electronics.