Resistive Switching Properties through Iodine Migrations of a Hybrid Perovskite Insulating Layer

This study reports a low‐temperature processable, resistive switching (RS) device based on an inorganic–organic hybrid perovskite, i.e., methylammonium lead iodide (CH 3 NH 3 PbI 3 or MAPbI 3 ) via a fast deposition–crystallization method, as the multifunctional insulator layer to form metal/insulator/metal structure in which Al and p + ‐Si wafer are used as the top and the bottom metal electrodes, respectively. The MAPbI 3 ‐RS device shows acceptable RS characteristics with a switching window of 10 3 at a low voltage region (≈5 V), a stable endurance during 200 cycles, and a high retention for a prolonged time at 10 4 s. The operation mechanism of the MAPbI 3 ‐RS device is based on ion (simultaneously vacancy) migration, especially iodine ions, which is analogous to that of oxygen ions in the conventional oxide‐based RS devices, confirmed through X‐ray photoelectron spectroscopy and energy‐dispersive X‐ray spectroscopy measurements. Furthermore, unusual multiresistance states are achieved from the MAPbI 3 ‐RS device under light illumination due to the photosensitivity of MAPbI 3 .