All‐In‐One Hardware Devices with Event‐Based Vision Sensor Arrays for Image Sensing, Computing, and Learning

Abstract

Metal oxide semiconductors (MOSs) are considered as potential candidates for the low‐cost, large‐area fabrication of flexible optoelectronic devices. However, the current optoelectronic devices based on MOSs are limited to unidirectional photoresponse, which constrains the performance of MOSs‐based vision sensors for artificial vision systems. Herein, for the first time, a flexible artificial vision system integrated with optical perception, computation, and learning functionalities is demonstrated using SnO optoelectronic synaptic transistor‐based event‐driven vision sensors to enable dynamic image perception, noise reduction, detection, and recognition. Specifically, an ambipolar SnO transistor is demonstrated by introducing HfO2 passivation layer, which facilitates the movement of O atoms around Sn‐vacancy sites to the HfO2 layer to achieve the transformation from p‐type to ambipolar transport behaviors. More importantly, the HfO2‐passivated SnO transistors exhibit gate‐tunable bidirectional photoresponse behavior, which is essential to simulate the neurobiological functionalities of bipolar cells. This way, the multilayer neural network learning circuit built from SnO transistors achieves fast recognition at a 16% Gaussian noise level and high recognition accuracy up to 95.2% for pattern letters. Under the bending states, recognition accuracies are still retained at 91.2%. These properties are well retained even under the influence of 100% offset of the synaptic programming value.

Reservoir Computing Based on Oxygen-Vacancy-Mediated X-ray Optical Synaptic Device for Medical CT Bone Diagnosis

“…A pair of X-ray optical pulses (79.38 mGy/s, pulse width = 2 s) are applied to the device, and the PPF effect of the device is shown schematically in Figure 4b. Their PPF indexes can be calculated by A 2 /A 1 = 1 + C 1 exp(−Δt/τ 1 ) + C 2 exp(−Δt/τ 2 ), 52 where C 1 and C 2 are the initial amplitudes of the fast and slow relaxation processes, and τ 1 and τ 2 are the This result is also consistent with the variation trend of the response speed of the three devices (Figure 4a). The reason for this phenomenon may be due to the more obvious persistent photoconductivity (PPC) effect with the increase in oxygen flux during the growth of Ga 2 O 3 films.…”

“…A pair of X-ray optical pulses (79.38 mGy/s, pulse width = 2 s) are applied to the device, and the PPF effect of the device is shown schematically in Figure b. Their PPF indexes can be calculated by A 2 / A 1 = 1 + C 1 exp­(−Δ t /τ 1 ) + C 2 exp­(−Δ t /τ 2 ), where C 1 and C 2 are the initial amplitudes of the fast and slow relaxation processes, and τ 1 and τ 2 are the time constants of the two processes. The interval of the two pulses is changed from 1 to 50 s, the PPF indexes of the three devices are measured separately, and the results and trends are shown in Figure c.…”

A Reconfigurable All-Optical-Controlled Synaptic Device for Neuromorphic Computing Applications

“…In addition, an effective strategy is to rely on the modulating impact of the gate voltage on the channel in the phototransistor. Simultaneously, by employing the heterostructure (WSe 2 /h-BN/Al 2 O 3 , Cl 2 –NDI/PBI-1, PdSe 2 /MoTe 2 ) or channel with bipolar conductivity (SnO/HfO 2 , DTT-8/TFT-CN), the phototransistor is capable of exhibiting a bidirectional photoresponse when the gate voltage is altered. The effectiveness of this strategy is contingent upon modulating the application of light with the gate voltage, hence increasing the complexity of the device construction.…”

Highly Stretchable and Oriented Wafer-Scale Semiconductor Films for Organic Phototransistor Arrays

“…Inspired by biological vision systems, retina-like photodetectors that mimic the structural and functional features of human retinas have attracted widespread attention. − It not only makes it possible for some blind people to regain vision but also enhances human vision by multifunctional photodetectors such as the retina. , Importantly, the bioinspired photodetectors are required to be similar to the curvature of the human retinas to perceive external light signals. , There are primarily two strategies to construct these photodetectors containing micronano devices. One is the direct manufacturing of micronano devices on curved support substrates, which requires addressing significant technical challenges. − Another method possesses two steps; the first step is to place initially manufactured micronano devices on a flexible planar substrate.…”