Two-Dimensional Near-Atom-Thickness Materials for Emerging Neuromorphic Devices and Applications

Abstract

Summary Two-dimensional (2D) layered materials and their heterostructures have recently been recognized as promising building blocks for futuristic brain-like neuromorphic computing devices. They exhibit unique properties such as near-atomic thickness, dangling-bond-free surfaces, high mechanical robustness, and electrical/optical tunability. Such attributes unattainable with traditional electronic materials are particularly promising for high-performance artificial neurons and synapses, enabling energy-efficient operation, high integration density, and excellent scalability. In this review, diverse 2D materials explored for neuromorphic applications, including graphene, transition metal dichalcogenides, hexagonal boron nitride, and black phosphorous, are comprehensively overviewed. Their promise for neuromorphic applications are fully discussed in terms of material property suitability and device operation principles. Furthermore, up-to-date demonstrations of neuromorphic devices based on 2D materials or their heterostructures are presented. Lastly, the challenges associated with the successful implementation of 2D materials into large-scale devices and their material quality control will be outlined along with the future prospect of these emergent materials.

Memristor Based on Inorganic and Organic Two-Dimensional Materials: Mechanisms, Performance, and Synaptic Applications

“…The past 3–5 years have witnessed substantial advances of 2D materials in memristors as well as memristor-based artificial synaptic systems. , Reliable and stable nonvolatile RS behaviors have been reported in 2D monolayers of transition metal dichalcogenides (TMDCs) and hexagonal boron nitride ( h -BN). , Because of the unique 2D layered structure, which is beneficial to size scaling, 2D materials with outstanding electrical properties have demonstrated advantages in RS devices. Although there are some limitations in the development of high-density electronic circuits based on 2D materials by considering the size limitations for device fabrication and the device-to-device variability, a large number of 2D materials have been employed to investigate the physical mechanism of RS and improve the RS performances of the fabricated memristors . In addition to serving as electrodes in memristors, graphene is generally used as a blocking layer between the switching layer and electrodes to improve the device stability and achieve the robust features. , Graphene can also be used as a charge-storage layer to construct a flash device .…”

“…Although there are some limitations in the development of high-density electronic circuits based on 2D materials by considering the size limitations for device fabrication and the device-to-device variability, a large number of 2D materials have been employed to investigate the physical mechanism of RS and improve the RS performances of the fabricated memristors. 9 In addition to serving as electrodes in memristors, graphene is generally used as a blocking layer between the switching layer and electrodes to improve the device stability and achieve the robust features. 10,11 Graphene can also be used as a charge-storage layer to construct a flash device.…”

Ferroelectric memory based on two-dimensional materials for neuromorphic computing

“…As yet, the majority of the reported 2D materialsbased ferroelectric synaptic devices were based on exfoliated nanoflakes and remained at the single device level. Large-scale synthesis of high-quality 2D thin films with uniform and controllable thickness is thus crucial for industrial-scale practical use of 2D ferroelectric synaptic devices [104]. Nevertheless, large-scale synthesis of some typical 2D semiconductor layers has been demonstrated with great promise [105][106][107][108].…”

Two-dimensional materials for artificial synapses: toward a practical application

“…Whether the reported synaptic behaviors of those 2DM synapses meet the requirement for practical applications remains in doubt. Many excellent review papers have systematically summarized 2DM synapses from the perspectives of materials and devices [14][15][16][17][18][19][20][21][22][23][24][25]. However, a comprehensive and quantitative study that connects to system-level requirements is still lacking.…”