Resistive Switching Layer-Modulated Volatile and Nonvolatile Memristors with Flexible and Controlled Transient Properties

A growing concern for sustainable electronics to support a more eco-friendly future has significantly increased the demand for flexible and biodegradable electronics. This work explores the effect of using entirely biocompatible materials in the memristor device to achieve volatile and nonvolatile resistive switching operations by modulating the switching layer (SL) materials. The physically transient memristors (PTMs), based on an Mg electrode, a polytrimethylene carbonate (PTMC)/polyvinylpyrrolidone (PVP) switching layer, and a chitosan/PVP substrate, exhibited both volatile and nonvolatile memory characteristics, as well as quantized conductance (G₀) states. The PTM device has a low set/reset voltage (<1 V), a large memory (R_OFF/R_ON) window (>10⁶), and long-term HRS/LRS retention (>10³ s) characteristics during its nonvolatile operation. The <i>I</i>-<i>V</i> and pulse response revealed that switching occurs due to the constriction of the Mg metallic filament to the atomic scale, with a resistance ≤ 12.9 kΩ. The LRS and HRS are controlled within the range of quantized conductance (G₀ = 2e²/h) to bulk conductance (G) states. The three different concentrations (1:0.5, 1:1, and 1:1.5) of blended film (PTMC:PVP) exhibit volatile resistive switching operation. The blended polymer films display a unique dual-phase surface morphology, facilitating ionic transportation. The device was encapsulated using an ALD-deposited Al₂O₃ layer to enable a controllable biodegradation process, allowing control over its lifespan. The tunable volatile/nonvolatile electrical characteristics and controllable biodegradation demonstrate the potential of this device for implantable biomedical memory, secure hardware systems, and flexible wearable electronics.