Interfacial resistive switching properties of Sr2TiO4/SrTiO3 heterojunction thin films prepared via sol-gel process

Abstract Layered perovskite SrO(SrTiO3)n (n = 1) and conventional perovskite SrTiO3 were fabricated as a heterojunction thin-film device. The Sr2TiO4/SrTiO3 heterostructure exhibited markedly improved resistive switching (RS) properties over single-phase Sr2TiO4 and pure strontium titanate. The other characteristics of the heterostructure, including stabilisation, high-pressure performance, and fatigue resistance, were investigated. The results showed a switch ratio of over 102, indicating a good RS effect. Various characterisation methods, such as X-ray diffraction, field emission scanning electron microscopy, and atomic force microscopy, were applied to analyse the crystal phase and surface morphology of the Sr2TiO4/SrTiO3 heterojunction thin film. The interfacial conduction mechanism was explained with an appropriate diagram. This study is the first to apply a first-principles analysis based on the density functional theory to elaborate the experimental results at the micro-level. The research provides a deeper understanding of the role of specific defects due to the heterostructure, which are strongly related to interface contact, and promotes the performance of Ruddlesden–Popper-phase strontium titanate, which has potential applications in resistive random access memory devices.