Resistive switching properties and photoelectric synaptic behavior of multilayer structured Au/Ce:HfO2/Al2O3/Ce:HfO2/FTO films

Abstract

Resistive random memories exhibit significant potential for non-volatile memory and artificial synaptic device advancements. In this work, Ce:HfO₂/Al₂O₃/Ce:HfO₂ multilayer films were synthesized via the sol-gel method. The resistive switching properties and synaptic behaviors of these films, with varying doping levels, were examined. Gold (Au) and fluorine-doped tin oxide (FTO) electrodes were used for the measurements. Current-voltage measurements revealed that all devices demonstrated bipolar resistive switching characteristics. Devices with a 12 % Ce doping concentration showed reliable switching ratios (>10²) over 100 cycles. The conductivity mechanisms in HRS and LRS were analyzed through double logarithmic I-V curves. In addition, devices doped with 8 % Ce concentration exhibit analog-type resistive switching behavior and possess photoelectric synaptic properties that effectively mimic biological synaptic behavior. Finally, a convolutional neural network was constructed using the MNIST and Fashion_MNIST datasets to verify the applicability of the device in the field of neuromorphic computing. These results offer a promising new avenue for non-volatile storage and neuromorphic computing development.