ZnO Nanoparticle-Induced Performance Enhancement of a Coumarin-Based Nonvolatile Memory Device

Abstract

Resistive switching memory devices based on organic as well as organic–inorganic hybrid materials are emerging as viable candidates for post-Moore nonvolatile memory applications. In this article, we report a nonvolatile write-once-read-many (WORM) resistive switching memory device (Al/7HNO3C/ITO) based on a coumarin derivative 7-hydroxy-N-octadecyl coumarin-3-carboxamide (7HNO3C). The device yield, retention time, read endurance, and memory window of the designed memory device were found to be 36.11%, 4 × 103 s, 1270 cycles, and ∼102, respectively. ZnO nanoparticles were synthesized and incorporated into the active layer of the coumarin-based device in order to enhance the memory performance of the device. The ZnO-incorporated device showed overall improvement in terms of device yield (83.33%), retention time (experimentally 3 × 104 s, extrapolated 10 years), read endurance (9930 cycles), and memory window (∼103) along with a significant decrease in the device-to-device variability. Moreover, density functional theory (DFT) studies and temperature-dependent measurements have revealed that charge transfer and oxygen vacancy filament formation were the key mechanisms behind such an observed memory behavior.