**Abstract**

In this chapter, we study factors that dominate the interfacial resistive switching (RS) in memristive devices. We have also given the basic understanding of different type of RS devices which are predominantly interfacial in nature. In case of resistive random access memory (RRAM), the effect of surface properties on the bulk cannot be neglected as thickness of the film is generally below 100 nm. Surface properties are effected by redox reactions, interfacial layer formation, and presence of tunneling barrier. Surface morphology affects the band structure in the vicinity of interface, which in turn effects the movements of charge carriers. The effect of grain boundaries (GBs) and grain surfaces (GSs) on RS have also been discussed. The concentration of vacancies (Ov)/traps/defects is comparatively higher at GBs which leads to leakage current flow through the GBs predominantly. Such huge presence of charge carriers causes current flow through grain boundaries.

**Keywords:** resistive switching, interface, grain boundary, oxygen vacancy, surface morphologies
