Memristor Based on TiO x /Al2O3 Bilayer as Flexible Artificial Synapse for Neuromorphic Electronics

Flexible memristor is one of the most promising wearable devices for abundant data storage and processing. In this work, interface engineering by inserting the Al ₂ O ₃ barrier layer is carried out to construct Pt/TiO _x /Al ₂ O ₃ /Pt/indium tin oxide (ITO) flexible artificial synapse device. The memristor performance can be maintained even under 1000 times of bending without degradation, demonstrating its excellent mechanical property. With the Al ₂ O ₃ diffusion barrier layer, the oxygen vacancies ( ${V}_{\text {o}}$ ) movement is slowed down for filaments formation and rupture, thus it boosts up the synaptic plasticity, including long-term potentiation/depression, paired-pulse facilitation (PPF), and spike-timing-dependent plasticity (STDP). Moreover, on the basis of the enhanced symmetry and linearity of conductance for Pt/TiO _x /Al ₂ O ₃ /Pt/indium tin oxide (ITO) memristor, the neural network simulation for supervised learning presents an online learning pattern recognition, the accuracy can achieve to 91.15%. Overall, the Pt/TiO _x /Al ₂ O ₃ /Pt/ITO memristor with excellent flexibility is a promising emulator for biological synapses, which could be beneficial to future flexible memristor-based neuromorphic computing.