Analog and bipolar resistive switching behavior in 'p-n' junction of the p-type BEFO/n-type ZnO heterostructures

Nonvolatile resistive random access memory (RRAM) exhibits potential applications in logic devices and provides a hardware foundation for neuromorphic computing. Here, based on the (16-x)Bi₀.₉₅Er_0.05FeO₃/(x)ZnO heterostructures ((16-x)BEFO/(x)ZnO; x is 0, 4, 5, 6 and 7 layers, respectively) are prepared using the sol-gel technique. The influence of the ZnO layer thickness on the conduction mechanism of resistive switching (RS) behavior is investigated. The RS behavior is attributed to ion migration and the change in barrier height. The x = 5 sample shows the largest high resistance state/low resistance state (HRS/LRS) ratio of over 10². All heterostructures exhibit excellent I-V cycling curves, endurance characteristics, and virtually no degradation trend after 30 cycles and 1000 operations. Further, the characteristics of biological synapses have been effectively simulated.