In situ edge extraction enabled by reconfigurable van der Waals infrared photodetectors

At present, the widely used artificial intelligence image perception technology is composed of discrete detection and processing components, which is mismatching the demand for increasingly sizeable redundant image information processing. The transmission of non-critical information between components limits the efficiency of image perception systems. Inspired by the human vision system, which can extract the key features and reduce the transmission burden at the low-level detection end, we propose a symmetric structured mixed-dimensional n/p/n [n-molybdenum disulfide (MoS2)/p-germanium (Ge)/n-MoS2] interdigital van der Waals heterojunction infrared photodetector that can be tuned by bias voltage in response polarity and magnitude. The MoS2/Ge/MoS2 infrared photodetector has a bias-symmetric optoelectronic response and covers the detection band from visible to short-wave infrared. Through the joint detection of a pair of MoS2/Ge/MoS2 infrared photodetectors, we demonstrate the image in situ edge extraction at the detection end, which provides key features for high-level processing. This work has discovered the potential of retina-inspired infrared photodetectors on a 2D/3D integration platform, providing distinct opportunities for a neuromorphic visual perception hardware.