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Neuromorphic computing holds promise for building next-generation intelligent systems in a more energy-efficient way than the conventional von Neumann computing architecture. Memristive hardware, which mimics biological neurons and synapses, offers high-speed operation and low power consumption, enabling energy-and area-efficient, brain-inspired computing. Here, recent advances in memristive materials and strategies that emulate synaptic functions for neuromorphic computing are highlighted. The working principles and characteristics of biological neurons and synapses, which can be mimicked by memristive devices, are presented. Besides device structures and operation with different external stimuli such as electric, magnetic, and optical fields, how memristive materials with a rich variety of underlying physical mechanisms can allow fast, reliable, and low-power neuromorphic applications is also discussed. Finally, device requirements are examined and a perspective on challenges in developing memristive materials for device engineering and computing science is given.

Keywords: artificial synapses; memristive materials; neurons; synaptic plasticity.

© 2021 Wiley-VCH GmbH.

The artificial synapse array with an electrolyte-gated transistor (EGT) as an array unit presents considerable potential for neuromorphic computation. However, the integration of EGTs faces the drawback of the conflict between the polymer electrolytes and photo-lithography. This study presents a scheme based on a lateral-gate structure to realize high-density integration of EGTs and proposes the integration of 100 × 100 EGTs into a 2.5 × 2.5 cm² glass, with a unit density of up to 1,600 devices cm^-2. Furthermore, an electrolyte framework is developed to enhance the array performance, with ionic conductivity of up to 2.87 × 10^-3 S cm^-1 owing to the porosity of zeolitic imidazolate frameworks-67. The artificial synapse array realizes image processing functions, and exhibits high performance and homogeneity. The handwriting recognition accuracy of a representative device reaches 92.80%, with the standard deviation of all the devices being limited to 9.69%. The integrated array and its high performance demonstrate the feasibility of the scheme and provide a solid reference for the integration of EGTs.

Keywords: Photo-Lithography; artificial synapse array; electrolyte-gated transistors; lateral-gate; metal-organic framework.

© 2023 The Authors. Advanced Science published by Wiley-VCH GmbH.

Current computing systems rely on Boolean logic and von Neumann architecture, where computing cells are based on high-speed electron-conducting complementary metal-oxide-semiconductor (CMOS) transistors. In contrast, ions play an essential role in biological neural computing. Compared with CMOS units, the synapse/neuron computing speed is much lower, but the human brain performs much better in many tasks such as pattern recognition and decision-making. Recently, ionic dynamics in oxide electrolyte-gated transistors have attracted increasing attention in the field of neuromorphic computing, which is more similar to the computing modality in the biological brain. In this review article, we start with the introduction of some ionic processes in biological brain computing. Then, electrolyte-gated ionic transistors, especially oxide ionic transistors, are briefly introduced. Later, we review the state-of-the-art progress in oxide electrolyte-gated transistors for ionic neuromorphic computing including dynamic synaptic plasticity emulation, spatiotemporal information processing, and artificial sensory neuron function implementation. Finally, we will address the current challenges and offer recommendations along with potential research directions.

Keywords: bio-inspired computing; ionic transistors; oxide semiconductors.

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Memristive devices with both electrically and optically induced synaptic dynamic behaviors will be crucial to the accomplishment of brain-inspired neuromorphic computing systems, in which the resistive materials and device architectures are two of the most important cornerstones, but still under challenge. Herein, kuramite Cu3SnS4 is newly introduced into poly-methacrylate as the switching medium to construct memristive devices, and the expected high-performance bio-mimicry of diverse optoelectronic synaptic plasticity is demonstrated. In addition to the excellent basic performances, such as stable bipolar resistive switching with On/Off ratio of ∼486, Set/Reset voltage of ∼-0.88/+0.96 V, and good retention feature of up to 104 s, the new designs of memristors possess not only the multi-level controllable resistive-switching memory property but also the capability of mimicking optoelectronic synaptic plasticity, including electrically and visible/near-infrared light-induced excitatory postsynaptic currents, short-/long-term memory, spike-timing-dependent plasticity, long-term plasticity/depression, short-term plasticity, paired-pulse facilitation, and “learning-forgetting-learning” behavior as well. Predictably, as a new class of switching medium material, such proposed kuramite-based artificial optoelectronic synaptic device has great potential to be applied to construct neuromorphic architectures in simulating human brain functions.

© 2023 Author(s). Published under an exclusive license by AIP Publishing.

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More than 3.5 billion years ago, life on Earth emerged from chemical reactions. Nature invented RNA, proteins, and DNA, the core molecules of life, and created the ribosome, a molecular factory that builds proteins from instructions in the genome.

Proteins are wondrous dynamic molecules with incredible functions—from molecular engines that power motion, to photosynthetic machines that capture light and convert it to energy, scaffolding that builds the internal skeletons of cells, complex sensors that interact with the environment, and information processing systems that run the programs and operating system of life. Proteins underlie disease and health, and many life-saving medicines are proteins.

Biology is the most advanced technology that has ever been created, far beyond anything that people have engineered. The ribosome is programmable—it takes the codes of proteins in the form of RNA and builds them up from scratch—fabrication at the atomic scale. Every cell in every organism on earth has thousands to millions of these molecular factories. But even the most sophisticated computational tools created to date barely scratch the surface: biology is written in a language we don’t yet understand.

Scientific Reports — Impact of device scaling on the electrical properties of MoS2 field-effect transistors.

Rzeszut, P., Chȩciński, J., Brzozowski, I. et al. Multi-state MRAM cells for hardware neuromorphic computing. Sci Rep 12, 7,178 (2022). https://doi.org/10.1038/s41598-022-11199-4

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Logic operations and reconfigurable circuits are demonstrated that can be directly implemented using memory elements based on floating-gate field-effect transistors with monolayer MoS2 as the active channel material.

Since the most advanced nodes in silicon are reaching the limits of planar integration, 2D materials could help to advance the semiconductor industry. With the potential for use in multifunctional chips, 2D materials offer combined logic, memory and sensing in integrated 3D chips.