Complementary Resistive Switching in ZnO/Al2O3 Bi-Layer Devices

This paper reports the complementary resistive switching (CRS) characteristics exhibited by Au/ZnO/Al
₂
O
₃
/ Fluorine doped tin oxide (FTO) bilayer device for the first time, where both ZnO and Al
₂
O
₃
are active switching layers exhibiting resistive switching properties. The I-V characteristics of the device initially show bipolar resistive switching (BRS) for a few cycles (∼12) before permanently switching to CRS with the extension of SET voltage. The stable CRS state of the device exhibits a high current of ∼500 μA during the ON-state and low current of 3 × 10
⁻⁷
A during OFF-state at low input voltages (−0.5 V to 0.5 V) enables the proposed device suitable to use in crossbar array to mitigate the sneak path current. The device performance to write and read processes is evaluated with pulses of magnitudes ∼|2.5| V and 1.3 V, respectively, and showed a ∼60 μA difference in read-out current between data bits 0 and 1. Similarly, the device's power consumption is also measured to elucidate that the device is suitable to use as a memory unit with power consumption in the order of microwatts (μW). Further, the possible switching mechanism is demonstrated based on oxygen vacancies migration.