Resistive switching behaviors and conduction mechanisms of IGZO/ZnO bilayer heterostructure memristors

This study delves into the characterization of IGZO/ZnO bilayer memristors, examining the impact of ZnO thickness and voltage scan rate on device performance. Bilayer memristors with varying ZnO thicknesses were prepared using magnetron sputtering, and their electrical properties were evaluated. The results indicate that a ZnO thickness of 17.3 nm yields optimal device performance, characterized by lower Forming and RESET voltages, reduced operating voltage volatility, higher switching ratios, and excellent cycling endurance and state retention. As the ZnO thickness increases, the Forming and RESET voltages of the devices also increase, the high resistance state volatility increases, and the switching ratio improves, although this is accompanied by greater operating voltage volatility. I–V characteristic measurements conducted at different scan rates revealed that the devices are insensitive to voltage scan rates, exhibiting stable resistive behavior within the range of 0.125–1.0 V/s. Furthermore, the study explores the multi-value storage capability of the bilayer device. To understand the resistive switching mechanism, current conduction mechanism fitting and resistive switching modeling were performed. The findings demonstrate that the device’s current conduction mechanism primarily involves the space-charge-limited current mechanism and Schottky emission mechanism. This research presents a novel approach to developing high-performance memristors, paving the way for their applications in nonvolatile storage and neuromorphic computing.