A TaO_x/TiO_y Bilayer Memristor with Enhanced Synaptic Features for Neuromorphic Computing

Memristors are a candidate device for artificial neural systems due to their excellent conductance-regulation ability and potential to simulate the characteristics of biological synapses. This study fabricated a Pt/TaOx/TiOy/Ti analog artificial synapse memristor that exhibits excellent multilevel storage property with a large on/off ratio of approximate to 660 times. The dynamic resistive switching mechanism is well expounded and validated by the reset stopping voltage dependent Schottky fitting results. Moreover, the essential biological synaptic characteristics such as long-term potentiation/depression (LTP/D) and paired-pulse facilitation (PPF) are successfully mimicked with a low pulse energy consumption of 12.69 nJ. A neuromorphic network constructed on the enhanced symmetry and linearity of conductance for this Pt/TaOx/TiOy/Ti memristive device can achieve 92.45% accuracy in recognizing handwritten pattern. These results demonstrate a significant potential for application Pt/TaOx/TiOy/Ti memristor in non-volatile memory and bioinspired neuromorphic systems.