Ke Chang,Xinna Yu,Wei Ren,Yunyang He,Zhikai Gan,Saiqun Ma,Huanpei Huang,Xianmin Jin,Yafei Zhang,Hui Wang
Semiconductor heterostructures can be used to explore band structures for creating optoelectronic devices. In this work, we demonstrate an all-optical-driven artificial vision system based on a porous silicon heterojunction with in-sensor processing capabilities. The abundant surface states of porous silicon enable light trapping and photoelectric conversion, which allow the sensor to exhibit high sensitivity and detect weak light signals. By utilizing differential optoelectronic signals, the integrated device can perform multiple functions within a single unit, such as in-sensor encoding and trajectory tracking of dynamic optical signals. The neuromorphic vision systems based on this photoelectric retina can perform optoelectronic modulation, trajectory reconstruction, and handwritten text recognition and can emulate functions of the human retina with temporal and spatial resolution. The design strategy here can be used to implement in-sensor processing of dynamic optical signals in machine vision systems.
Ruifu Zhou,Wenxin Zhang,Haofei Cong,Yu Chang,Fengyun Wang,Xuhai Liu
The multi-terminal transistor can provide reliable platform to construct artificial synapses with various benefits. In particular, synaptic transistors based on wide-bandgap metal oxide semiconductors (MOSs) offer opportunities to realize ultraviolet (UV) artificial vision. In this work, via a low-cost electrospinning technique, we have fabricated bio-inspired synaptic transistors based on zinc tin oxide (ZnSnO) nanowires, which can be effectively tuned by UV laser to achieve air-stable synaptic characteristics, such as excitatory post-synaptic current, paired-pulse facilitation, and learning-forgetting process based on long-term potentiation. The adsorption/desorption of oxygen molecules governs the generation of free charge carriers in the ZnSnO nanowires. Via the combination of transmission electron microscopy and X-ray diffraction measurements , we found that the revealed SnO 2 /ZnO heterostructures can effectively mitigate the recombination of UV-induced free carriers in the ZnSnO nanowires. Furthermore, based on the synaptic characteristics obtained from ZnSnO nanowires, we present several applications relevant to the UV artificial vision. We believe this study can provide insights into importance of heterostructures in synaptic transistors based on low-dimension MOSs with superior environmental stability and various applications.
Emulating human vision using solid-state devices is critical in the fields of robotics, artificial intelligence, and visual prostheses, driving intense research interest. However, bionic vision devices made from routine structures suffer from low light-perception sensitivity to nighttime low illuminations and high power consumption, impeding their applications in many advanced scenarios from nighttime autopilot to night vision neuroprosthesis. Here, an ultrasensitive and low-power-consumption organic phototransistor that consists of a unique Schottky-barrier structure and separated light absorption and carrier transport layers is reported. This device design shuns the introduction of trap states into the carrier transport route, which guarantees an ultra-steep subthreshold swing and thus significantly amplifies the photocurrent while lowering operation voltage. In consequence, the weak-light detection capacity for this device is enhanced dramatically, which can perceive nighttime low light illuminations with ultrahigh light-perception sensitivity of 10 2 –10 4 and low power consumption of <10 nW. Leveraging these findings, it is demonstrated that the phototransistor has neuromorphic vision perception behaviors and energy efficiency like human brain under faint light, opening a new opportunity for artificial vision.
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