Band‐tailored van der Waals heterostructure for multilevel memory and artificial synapse

Abstract

Two‐dimensional (2D) van der Waals heterostructure (vdWH)‐based floating gate devices show great potential for next‐generation nonvolatile and multilevel data storage memory. However, high program voltage induced substantial energy consumption, which is one of the primary concerns, hinders their applications in low‐energy‐consumption artificial synapses for neuromorphic computing. In this study, we demonstrate a three‐terminal floating gate device based on the vdWH of tin disulfide (SnS2), hexagonal boron nitride (h‐BN), and few‐layer graphene. The large electron affinity of SnS2 facilitates a significant reduction in the program voltage of the device by lowering the hole‐injection barrier across h‐BN. Our floating gate device, as a nonvolatile multilevel electronic memory, exhibits large on/off current ratio (~105), good retention (over 104 s), and robust endurance (over 1000 cycles). Moreover, it can function as an artificial synapse to emulate basic synaptic functions. Further, low energy consumption down to ~7 picojoule (pJ) can be achieved owing to the small program voltage. High linearity (<1) and conductance ratio (~80) in long‐term potentiation and depression (LTP/LTD) further contribute to the high pattern recognition accuracy (~90%) in artificial neural network simulation. The proposed device with attentive band engineering can promote the future development of energy‐efficient memory and neuromorphic devices.

Reconfigurable Quasi‐Nonvolatile Memory/Subthermionic FET Functions in Ferroelectric–2D Semiconductor vdW Architectures

“…As suggested by the fatigue data directly measured in the BiT flake, stable ferroelectric switching should be able to be maintained over 5 × 10 5 cycles. The endurance and retention are comparable to those of 2D van der Waals heterostructured floating-gate devices; [30,31] semifloating-gate devices; [32][33][34] and previously reported FeFETs fabricated using other ferroelectric materials, such as P(VDF-TrFE) copolymer, [35] lead zirconate titanate, [36] doped hafnium oxide, [37] and CuInP 2 S 6 . [9] It is known that oxygen vacancies drifting deeply into the bulk encounter difficulty in diffusing back to the FS interface, which normally requires a long period of time-ranging from days to years.…”

Coupling of N‐Doped Mesoporous Carbon and N‐Ti3C2 in 2D Sandwiched Heterostructure for Enhanced Oxygen Electroreduction

“…Especially, customizing electronic bandgaps in coupled heterostructures would allow control of the interfacial interaction for specific applications. [ 9–20 ]…”

“…Especially, customizing electronic bandgaps in coupled heterostruc tures would allow control of the interfacial interaction for specific applications. [9][10][11][12][13][14][15][16][17][18][19][20] In terms of constructing a 2D hetero geneous structure, selecting a 2D platform is important, which is expected to possess excellent mechanical strength and elec trical conductivity. MXene, an emerging type of 2D materials, has been manufac tured by selectively etching A elements (group III A or IV A) of MAX phases.…”

Highly-Responsive Broadband Photodetector Based on Graphene-PTAA-SnS2 Hybrid

“…As a typical 2D TMDC, tin disulfide (SnS 2 ) has a wide bandgap within the range of 2.08–2.44 eV [ 23 , 24 ] and displays a competent experimental mobility of 230 cm 2 V −1 s −1 [ 25 ]. It is promising for sustainable optoelectronics and catalysis applications because of the extraordinary electronic and optical properties, earth-abundance, and environment-friendliness [ 26 , 27 , 28 , 29 , 30 , 31 ].…”