Optoelectronic Synaptic Devices for Neuromorphic Computing

Abstract

Neuromorphic computing can potentially solve the von Neumann bottleneck of current mainstream computing because it excels at self‐adaptive learning and highly parallel computing and consumes much less energy. Synaptic devices that mimic biological synapses are critical building blocks for neuromorphic computing. Inspired by recent progress in optogenetics and visual sensing, light has been increasingly incorporated into synaptic devices. This paves the way to optoelectronic synaptic devices with a series of advantages such as wide bandwidth, negligible resistance–capacitance (RC) delay and power loss, and global regulation of multiple synaptic devices. Herein, the basic functionalities of synaptic devices are introduced. All kinds of optoelectronic synaptic devices are then discussed by categorizing them into optically stimulated synaptic devices, optically assisted synaptic devices, and synaptic devices with optical output. Existing practical scenarios for the application of optoelectronic synaptic devices are also presented. Finally, perspectives on the development of optoelectronic synaptic devices in the future are outlined.

Spectrum‐dependent photonic synapses based on 2D imine polymers for power‐efficient neuromorphic computing

“…The evolution of optogenetics in neuroscience has recently stimulated intense interest on photonic synapses 15,16 . The employment of optical modulation is suitable not only for high energy efficiency and ultrahigh computing speed, but also for visual‐perception systems 17‐22 . Recently, many studies on photonic synapses based on carbon nanotubes, 23,24 perovskites, 25‐30 nanodots, 31 and 2D materials, 32‐34 have been demonstrated for neuromorphic computing.…”

Memristive Artificial Synapses for Neuromorphic Computing

“…Synaptic plasticity is the experience-dependent change in the connection strength between neurons and is well described by the Hebbian theory [ 5 , 6 , 11 ]. This plasticity comes in different types depending on the shape of external pulses [ 12 ]. The different types include short-term potentiation/depression (STP/STD) such as paired pulse facilitation (PPF)/paired pulse depression (PPD) and spike-number-dependent plasticity (SNDP), long-term potentiation/depression (LTP/LTD), spike-rate-dependent plasticity (SRDP), and spike-timing-dependent plasticity (STDP).…”

“…Thus, synaptic devices have been constructed based on these properties of various functional material-based memristive systems and studied the synaptic behaviors in response to external stimulation signals [ 13 ]. These signals mainly include electrical and optical pulses, which exhibit many advantages in regulating physical properties of these material-based devices and thereby mimicking synaptic functions [ 2 , 4 , 12 , 14 ]. In the work, we discuss these synaptic devices by categorizing them into electrically stimulated, optically stimulated, and photoelectric synergetic synaptic devices.…”

A hippocampus-inspired illumination time-resolved device for neural coding

“…Recently, optically stimulated synaptic devices are well-known for wide bandwidth, low power consumption, fast signal propagation speed and efficient interconnect, which contribute to neuromorphic computing and mimicking neural activities [9][10][11][12][13]. For example, optically stimulated synaptic devices have been applied to mimic the memory storage of the brain, such as short term memory (STM) and long term memory (LTM) which are two important components of the Atkinson-Shiffrin memory model [9,14,15]. Nevertheless, the full memory function has been rarely reported, and the proposed mechanisms have remained unknown.…”

“…These defects can trap charge carriers for a long moment while the detrapping process of charge carriers can be extremely slow [32]. The well-accepted trapping/detrapping processes can be caused by crystal defects, semiconductor/dielectric interfaces and heterojunctions [9,[33][34][35][36][37]]. Park's group [13] verified that the PPC effect in ReS 2 resulted from sulphur vacancies via density functional theory (DFT) calculations.…”