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Memristor-based neuromorphic computing is expected to overcome the bottleneck of von Neumann architecture. An artificial synaptic device with continuous conductance variation is essential for implementing bioinspired neuromorphic systems. In this work, a memristor based on Pt/LiSiO x /TiN structure is developed to emulate an artificial synapse, which shows non-volatile multilevel resistance state memory behavior. Moreover, the high nonlinearity caused by abrupt changes in the set process is optimized by adjusting the initial resistance. 100 levels of continuously modulated conductance states are achieved and the nonlinearity factors are reduced to 1.31. The significant improvement is attributed to the decrease in the Schottky barrier height and the evolution of the conductive filaments. Finally, due to the improved linearity of the long-term potentiation/long-term depression behaviors in LiSiO x memristor, a robust recognition rate (∼94.58%) is achieved for pattern recognition with the modified National Institute of Standards and Technology handwriting database. The Pt/LiSiO x /TiN memristor shows significant potential in high-performance multilevel data storage and neuromorphic computing systems. [ABSTRACT FROM AUTHOR]

Hafnium oxides (HfOx) based flexible memristors were fabricated on polyethylene naphtholate (PEN) substrates to simulate a variety of bio-synapse functions. By optimizing the manufacturing conditions of electrode and active films, it is proved that the TiN/HfOx/W/ITO/PEN bilayer device has robust flexibility and can still be modulated after 2000 times of bending. The memristor device exhibits better symmetrical and linear characteristics with excellent uniformity at lower programming power consumption (∼38 μW). In addition, the essential synaptic behaviors have further been achieved in the devices, including the transition from short-term plasticity to long-term plasticity and spike time-dependent plasticity. Through the analysis of I–V curves and XPS data, a switching mechanism based on HfOx/W interface boundary drift is constructed. It is revealed that the redox reaction caused by W intercalation can effectively regulate the content of oxygen vacancy in HfOx. At the same time, bias-induced interfacial reactions will regulate the movement of oxygen vacancies, which emulates bio-synapse functions and improves the electrical properties of the device. [ABSTRACT FROM AUTHOR]

Both synaptic emulators and brain-like calculation demand an energy-efficient and bio-realistic device where two-dimensional materials have been proven as a promising competitor. Lateral memristors based on transfer-free single-crystal MoS2 with single layer grown by chemical vapor deposition (CVD) were fabricated. Here the MoS2 memristor successfully emulates typical biological synaptic behaviors including excitatory/inhibitory post-synaptic current (EPSC/IPSC), spike timing-dependent plasticity (STDP), spike rate-dependent plasticity (SRDP) and long-term plasticity (LTP). Moreover, an interesting multi-state LTP and a low consumption of 1.8 pJ after LTP process are achieved which is attributed to the high resistance of transfer-free single-crystal monolayer MoS2, representing a low value among previous MoS2 devices. The migration of Sulfur vacancies lead the conductance modulation by changing the Schottky barrier instead of forming a filament. Our work demonstrates that MoS2 memristors can more flexibly satisfy the demands of complex artificial synaptic/neuron applications. [ABSTRACT FROM AUTHOR]

Memristor-based neuromorphic computing is expected to overcome the bottleneck of von Neumann architecture. An artificial synaptic device with continuous conductance variation is essential for implementing bioinspired neuromorphic systems. In this work, a memristor based on Pt/LiSiO x /TiN structure is developed to emulate an artificial synapse, which shows non-volatile multilevel resistance state memory behavior. Moreover, the high nonlinearity caused by abrupt changes in the set process is optimized by adjusting the initial resistance. 100 levels of continuously modulated conductance states are achieved and the nonlinearity factors are reduced to 1.31. The significant improvement is attributed to the decrease in the Schottky barrier height and the evolution of the conductive filaments. Finally, due to the improved linearity of the long-term potentiation/long-term depression behaviors in LiSiO x memristor, a robust recognition rate (∼94.58%) is achieved for pattern recognition with the modified National Institute of Standards and Technology handwriting database. The Pt/LiSiO x /TiN memristor shows significant potential in high-performance multilevel data storage and neuromorphic computing systems., (© 2023 IOP Publishing Ltd.)

Both synaptic emulators and brain-like calculation demand an energy-efficient and bio-realistic device where two-dimensional materials have been proven as a promising competitor. Lateral memristors based on transfer-free single-crystal MoS 2 with single layer grown by chemical vapor deposition (CVD) were fabricated. Here the MoS 2 memristor successfully emulates typical biological synaptic behaviors including excitatory/inhibitory post-synaptic current (EPSC/IPSC), spike timing-dependent plasticity (STDP), spike rate-dependent plasticity (SRDP) and long-term plasticity (LTP). Moreover, an interesting multi-state LTP and a low consumption of 1.8 pJ after LTP process are achieved which is attributed to the high resistance of transfer-free single-crystal monolayer MoS 2 , representing a low value among previous MoS 2 devices. The migration of Sulfur vacancies lead the conductance modulation by changing the Schottky barrier instead of forming a filament. Our work demonstrates that MoS 2 memristors can more flexibly satisfy the demands of complex artificial synaptic/neuron applications.