Enhanced synaptic weight in ferroelectric PbZr0.52Ti0.48O3 thin film by inserting semiconductor Sr2IrO4 layer

Abstract

Ferroelectric memristors based on metal/ferroelectric/semiconductor structure are suitable for the simulation of non-volatile synaptic weight due to the high on/off switching ratio, low energy consumption, high precision and fast working speed. Especially, the characteristics of the semiconductor electrode are closely related to the synaptic performance of the device. Here, ferroelectric memristors (PbZr0.52Ti0.48O3/Nb:SrTiO3 and PbZr0.52Ti0.48O3/Sr2IrO4) with different semiconductor electrodes were fabricated by introducing Sr2IrO4 (SIO) thin film. Various plasticity have been successfully simulated under different electrical impulses, such as inhibitory postsynaptic current (IPSC), paired pulse depression (PPD), spike rate dependent plasticity (SRDP) and spike time dependent plasticity (STDP) in the two devices. Moreover, the absolute values of synaptic weight and the relaxation time of PbZr0.52Ti0.48O3 (PZT)/SIO have been significantly improved. This may be attributed to the fact that the small work function of SIO increases the variation of the interface barrier at the device. And the artificial synaptic device based on PZT/SIO is used to achieve the application of Morse code. This study plays an important role in achieving efficient storage and computation for neuromorphic computing.