Effect of bending on resistive switching of NiO/ZnO nanocomposite thin films

The bending effects on resistive switching of NiO/ZnO nanocomposite thin films fabricated by sol-gel spin-coating method were investigated. The switching is induced by the cooperation of different Schottky barrier height at the NiO/ITO interface and the formation/rupture of tree-like filamentary paths due to the field-induced migration of oxygen vacancies and oxygen ions. The as-fabricated films showed obvious degradation in electrical properties upon bending. Structural analysis indicates that the samples can be treated as amorphous NiO films embedded with highly crystallized ZnO nanoparticles, and thus cracks may initiate and propagate along the NiO/ZnO interfaces and grain boundaries of NiO. Further finite element studies show that bending-induced heating and micro-cracks may facilitate the oxidization of the function layer and hinder the carrier transport. Our work may provide some useful information to further understand bending effects of flexible resistive random access memory devices.