Key Laboratory for Micro/Nano Optoelectronic Devices of Ministry of Education& Hunan Provincial Key Laboratory of Low-Dimensional Structural Physics and Devices, School of Physics and Electronics, Hunan University, Changsha, 410082, P. R. China.
Hunan Key Laboratory for Super Microstructure and Ultrafast Process, School of Physics and Electronics, Central South University, Changsha, 410083, P. R. China.
Adv Sci (Weinh). 2022 Sep;9(27):e2202019. doi: 10.1002/advs.202202019. Epub 2022 Jul 22.
The extraordinary optoelectronic properties and continued commercialization of GaN enable it a promising component for neuromorphic visual system (NVS). However, typical GaN-based optoelectronic devices demonstrated to data only show temporary and unidirectional photoresponse in ultraviolet region, which is an insurmountable obstacle for construction of NVS in practical applications. Herein, an ultrasensitive visual sensor with phototransistor architecture consisting of AlGaN/GaN high-electron-mobility-transistor (HEMT) and two-dimensional Ruddlesden-Popper organic-inorganic halide perovskite (2D OIHP) is reported. Utilizing the significant variation in activation energy for ion transport in 2D OIHP (from 1.3 eV under dark to 0.4 eV under illumination), the sensor can efficiently perceive and storage optical information in ultraviolet-visible region. Meanwhile, the photo-enhanced field-effect mechanism in the depletion-mode HEMT enables gate-tunable negative and positive photoresponse, where some typical optoelectronic synaptic functions including inhibitory and excitatory postsynaptic current as well as paired-pulse facilitation are demonstrated. More importantly, a NVS based on the proposed visual sensor array is constructed for achieving neuromorphic visual preprocessing with an improved color image recognition rate of 100%.
氮化镓 (GaN) 的非凡光电性能和持续商业化使其成为神经形态视觉系统 (NVS) 的有前途的组件。然而，迄今为止的数据表明，典型的基于 GaN 的光电设备仅在紫外区域表现出暂时的、单向的光响应，这对于实际应用中 NVS 的构建是一个不可逾越的障碍。在此，我们报道了一种具有光电晶体管结构的超灵敏视觉传感器，该结构由 AlGaN/GaN 高电子迁移率晶体管 (HEMT) 和二维 Ruddlesden-Popper 有机-无机卤化物钙钛矿 (2D OIHP) 组成。利用二维 OIHP 中离子输运的活化能显著变化（从黑暗下的 1.3 eV 变为光照下的 0.4 eV），该传感器可以有效地感知和存储紫外可见区域的光学信息。同时，耗尽模式 HEMT 中的光增强场效应机制可实现栅极可调的正负光响应，其中演示了一些典型的光电突触功能，包括抑制性和兴奋性突触后电流以及成对脉冲易化。更重要的是，基于所提出的视觉传感器阵列构建了一个 NVS，用于实现神经形态视觉预处理，从而将彩色图像识别率提高到 100%。
