**3.3 Multilevel resistive switching**

The potential of multilayer RS effect has been documented in several inorganic materials due to its superior memory performance, but the difficult fabrication

**Figure 4.** *I-V curves of Au/KCl-MAPIC/ITO/glass indicating two VSETs of 0.8 V and 1.0 V. Adapted from figure 3 [36].*

method and stiffness restrict the development for ReRAM [31–33]. Organometal halide perovskites (OHPs) have recently sparked a lot of interest in the ReRAM community because to the high flexibility, variable band gaps, huge absorption coefficients, and long electron-hole diffusion length [34, 35]. Furthermore, OHPs highly feature defect-tolerant, simple, and cost-effective solution-processed procedures for fabricating the OHPs layers. As a result, they envision it being used in multilevel RS, which is advantageous for multilevel data storage. Typically, these devices feature numerous resistance states that can be changed within the device. **Figure 4** shows a typical multilevel perovskite memory consisting of a all-inorganic CsPb1–*x*BixI3 perovskite film [36]. This reveal that multilevel RS was accomplished by altering the reset stop voltages.
