Analog-to-digital and self-rectifying resistive switching behavior based on flower-like δ-MnO₂

Memristors can be divided into two types, analog and digital, according to the characteristics of current gradients and sudden changes. It is particularly important to realize analog and digital switching behaviors in the same device to facilitate the development of analog–digital circuits. In this work, the flower-like δ-MnO₂ was prepared on fluorine doped tin oxide (FTO) substrate by chemical bath deposition method, and it can be used as dielectric layer of memristor. Analog and digital types of resistive switching behaviors were achieved in the same device with Ag/δ-MnO₂/FTO structure by adjusting the applied voltage range on top electrode of memristor. Moreover, the digital type of resistive switching behavior with multi-level and self-rectifying properties was realized in this device. The charge transport and resistive switching mechanism of the device with analog to multi-level self-rectifying digital types was explained by analyze its current–voltage (I-V) curve. Therefore, this new type of memristive device with both analog and digital properties can simplify the circuit complexity, and the multilevel and self-rectification behavior can greatly improve the storage density and solve the misreading problem of memristive devices.