Voltage-controlled resistive switching is demonstrated in various gap systems on SiO2 substrate. The nanosized gaps are made by different means using different materials including metal, semiconductor, and metallic nonmetal. The switching site is further reduced by using multi-walled carbon nanotubes and single-walled carbon nanotubes. The switching in all the gap systems shares the same characteristics. This independence of switching on the material compositions of the electrodes, accompanied by observable damage to the SiO2 substrate at the gap region, bespeaks the intrinsic switching from post-breakdown SiO2. It calls for caution when studying resistive switching in nanosystems on oxide substrates, since oxide breakdown extrinsic to the nanosystem can mimic resistive switching. Meanwhile, the high ON/OFF ratio (∼10 5 ), fast switching time (2 µs, test limit), durable cycles demonstrated show promising memory properties. The intermediate states observed reveal the filamentary conduction nature.Resistive switching in various materials such as metal oxides 1,2 , chalcogenides 3 and organic materials 4,5,6 has been intensively studied as candidates for future nonvolatile memories 7 . Recently, it also extends to new quasi-one dimensional (1D) and 2D materials such as encapsulated nanowires 8 , multi-walled carbon nanotubes (MWNTs) 9 , and graphene sheets 10 . In these nanostructures, the constriction in one dimension but less in the other(s) facilitates the observation of the switching events. The direct observations of nanosized gap or void structures in these systems come to similar switching mechanisms attributing to the electric close-and-break motion of the material at the gap/void region. Less attention has been paid on the substrate material of SiO 2 due to its good dielectric (insulating) property. Meanwhile, the amorphous form of SiO 11,12,13,14,15,16 or a defected SiO x surface 17 can exhibit memory phenomena, in which structural defects induced by high local field is one of the proposed causes 11 . For a gap system at nano size, it is expected that a high local field is built up during the switches between high-impedance (OFF) and low-impedance (ON) states. It therefore carries the significance to investigate the local field effect on the commonly used substrate material of SiO 2 . In the following context, we demonstrate resistive switching phenomena in various nanogap systems on SiO 2 substrate, made by different materials and means. The similar switching characteristics in all the systems point to the most likely cause: SiO 2 breakdown (BD) induced filaments, possibly through Si-Si wire formation. Shown in Fig. 1a, an initial gap system is a pair of tungsten (W) electrodes separated by ∼50 nanometers (nm) on a thermal-oxidized Si surface (the SiO 2 thickness is 200 nm, and same thickness is used for all the following devices), defined by standard electron beam lithography (EBL) and lift-off process. Electrical characterizations were performed using an Agilent 4155C semiconductor parameter analyzer i...