Clay Induced Performance Enhancement of a Plant Extract-Based WORM and RRAM for Sustainable Data Storage and Neuromorphic Computing Applications

Natural plant-material-based memory devices have been in the spotlight due to their versatile applications ranging from nonvolatile memory to neuromorphic computations. Locally available plant Nymphaea nouchali, whose vernacular English name is water lily (WL), leaves were used to design a resistive memory device having configuration Au/WL/ITO. The device exhibited write-once-read-many (WORM) behavior with memory window (∼10²), device yield (∼55%), read endurance (8000 times), and data retention (∼500 s). With the incorporation of synthetic clay mineral Laponite along with WL in the active layer, the device (Au/WL+Laponite/ITO) exhibited reliable resistive random-access memory (RRAM) behavior in addition to WORM based on the measurement protocol. In the Laponite-based device, the device performances improved significantly with higher retention time (up to 10 years), larger memory window (10⁴), greater device yield (88%) and higher read endurance (10 000 times). The cycle-to-cycle variability of the RRAM device has also been studied. The conduction mechanism of these memory devices is dominated by space charge limited conduction, Schottky emission, and conducting filament formation. Apart from that, in order to investigate the neuromorphic properties, several preliminary rules like the learning and forgetting nature of the RRAM device (potentiation and depression) have also been studied. Moreover, the plasticity of the artificial synapse has been studied by varying the pulse width, pulse amplitude, and pulse interval. The results suggest that these biodegradable as well as eco-friendly devices provide a greater prospective toward the sustainable electronics with RRAM and WORM memory applications as well neuromorphic computation.