Enhancement of data storage capability in a bilayer oxide-based memristor for wearable electronic applications

Abstract

In this work, a ZnO/NiO bilayer architecture is introduced to fabricate transparent and flexible resistive random access memory (RRAM) device (Cu/ZnO/NiO/ITO) on polyethylene terephthalate (PET) substrate. The device exhibits excellent RS characteristics, such as forming free characteristic, low operating voltages, outstanding uniformity, long retention time (>104 s), high ON/OFF current ratio ~103, reliable multilevel cell (MLC) characteristics and excellent mechanical flexibility. The multilevel properties has been systematically evaluated by varying the compliance current and by tuning the stopping voltage, which shows that all the resistance state are distinguishable and remained stable without any considerable deprivation over 103 s. Intrinsic tailoring of RS mechanism has been well explained in the framework of electric field-induced formation and rupture of the reproducible Cu filaments in ZnO/NiO layer. Further, the metallic nature of conducting filament has further been confirmed by temperature-dependent variation of the high and low resistance states. Owing to the increasing demand of flexible electronics, the mechanical robustness of the proposed device has been examined by varying bending time and radius. The present RS device shows potential toward integration in many transparent, flexible and high-density storage devices, such as electronic skins and flexible displays.