Anisotropic Black Phosphorus Synaptic Device for Neuromorphic Applications

Abstract

The first black-phosphorus synaptic device is demonstrated, which offers intrinsic anisotropy in its synaptic characteristics directly resulting from its low crystalline symmetry. Key features of biological synapses, such as long-term plasticity with heterogeneity, including long-term potentiation/depression and spike-timing-dependent plasticity, are mimicked. This demonstration represents an important step toward introducing intrinsic heterogeneity to artificial neuromorphic systems.

Protective molecular passivation of black phosphorus

“…2,5,6 Therefore, BP supports anisotropic optical and transport responses that can enable unique device architectures. 7 Its thickness-dependent direct bandgap varies in the range of 0.3-2.0 eV (from single-layer to bulk, respectively), making BP suitable to optoelectronics in a broad spectral range. [8][9][10] With high room-temperature mobility, exceeding 1000 cm 2 V −1 s −1 in thin films, BP is also a very promising material for electronics.…”

Bridging Biological and Artificial Neural Networks with Emerging Neuromorphic Devices: Fundamentals, Progress, and Challenges

“…[41,96,97] Importantly, these devices relax back to their highly resistive off state spontaneously (without the need of RESET operation) after firing, closely resembling the repolarization process of biological [75] Copyright 2016, Springer Nature. [123] Copyright 2016, Wiley. Adapted with permission.…”

“…[123,[140][141][142] Also, FETs based on silicon, organic materials, perovskite or carbon nanotube (CNT) have been reported as synaptic elements based on either charge trapping/detrapping mechanism or floating-gate (FG) memory structure, some of which have a structure of multi-gate FET. [120][121][122][123][124][125][126][127][128] Three-terminal FeFET and two-terminal ferroelectric tunnel junction (FTJ) relying on ferroelectric polarization switching have been explored as artificial synapses, where the pulsing scheme needs to be carefully designed to improve the switching symmetry and linearity. [94,103] Similarly, two-terminal spin-transfer torque MRAM (STT-MRAM) based on magnetization switching and multi-terminal magnetic devices based on domain wall motion have also been studied to implement artificial synapses.…”

Synaptic Barristor Based on Phase‐Engineered 2D Heterostructures

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The first step toward realizing a massively parallel neuromorphic system is to develop an artificial synapse capable of emulating diverse synaptic functionality, such as short-and long-term plasticity, [6][7][8] with ultralow power consumption and robust controllability. [9][10][11][12][13][14][15][16][17][18][19][20][21][22][23][24] In addition, many synaptic device architectures, such as resistive memories, memristors, electrochemical transistors, have been employed to emulate a biological synapse linked between presynaptic and postsynaptic neurons, in which synaptic plasticity is solely determined by spatiotemporal input spikes from only two neurons. [9][10][11][12][13][14][15][16][17][18][19][20][21][22][23][24] In addition, many synaptic device architectures, such as resistive memories, memristors, electrochemical transistors, have been employed to emulate a biological synapse linked between presynaptic and postsynaptic neurons, in which synaptic plasticity is solely determined by spatiotemporal input spikes from only two neurons.

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