High-Performance Flexible Resistive RAM with PVP:GO Composite and Ultrathin HfO<inf>x</inf> Hybrid Bilayer

Resistive switching behavior of poly (4-vinylphenol):graphene oxide (PVP:GO) composite and ultrathin HfOx hybrid bilayer was explored for developing high-performance flexible resistive random access memory (RRAM) devices. These devices, fabricated with a PVP:GO equivolume solution spin-coated and atomic layer deposited ultrathin HfOx as an active bilayer, exhibited excellent bipolar switching behavior with set and reset voltages as low as 0.6 and-1.46 V, ION/IOFF of >105, and ac and dc switching endurance of over 1400 and 800 cycles, respectively. The same device configuration realized over a flexible polyethylene terephthalate (PET) substrate exhibited a memory window of >103 even after undergoing large mechanical strain (correspoding to a 5-mm bending radius). In addition, after 150 cumulative cycles of consecutive tensile and compressive strain at a 5-mm bending radius, flexible RRAMs demonstrated a clear memory window of 4 × 103 for 104 s. Overall, the incorporation of GO into the PVP solution resulted in achieving better control over conductive filament (CF) growth and, therefore, improved repeatability and reliability. This article indicates that the strategy of incorporating composite and organic-inorganic active bilayer can lead toward the development of high-performance flexible RRAMs.