报告题目：Bioinspired vision sensors with 2D semiconductors
报告人：Prof. Yang Chai（柴扬）
报告人单位：Hong Kong Polytechnic University（香港理工大学）
时间：2023年10月27日3：30pm
地点：教2-327
主办单位：南京邮电大学理学院
邀请人：高丽
报告内容：Motion processing has proven to be a computational challenge and demands considerable computational resources. Contrast this with the fact that flying insects can agilely perceive real-world motion with their tiny vision system. Here we show that phototransistor arrays can directly perceive different types of motion at sensory terminals, emulating the non-spiking graded neurons of insect vision systems. The charge dynamics of the shallow trapping centres in MoS2 phototransistors mimic the characteristics of graded neurons, showing an information transmission rate of 1,200 bit s−1 and effectively encoding temporal light information. We used a 20 × 20 photosensor array to detect trajectories in the visual field, allowing the efficient perception of the direction and vision saliency of moving objects and achieving 99.2% recognition accuracy. Furthermore, we report computational event-driven vision sensors that capture and directly convert dynamic motion into programmable, sparse, and informative spiking signals. The sensors can be used to form a spiking neural network for motion recognition. Each individual vision sensor consists of two WSe2 parallel photodiodes with opposite polarities and has a temporal resolution of 5 μs. In response to changes in light intensity, the sensors generate spiking signals with different amplitudes and polarities by electrically programming their individual photoresponsivity. The nonvolatile and multilevel photoresponsivities of the vision sensors can emulate synaptic weights and can be used to create an in-sensor spiking neural network. Our computational event-driven vision sensor approach eliminates redundant data during the sensing process, as well as the need for data transfer between sensors and computation units.
报告人简介：Prof. Yang Chai is the Associate Dean of the Faculty of Science of the Hong Kong Polytechnic University, the Director of Joint Research Center of Microelectronics of PolyU, Vice President of the Physical Society of Hong Kong, a member of The Hong Kong Young Academy of Sciences, an IEEE Distinguished Lecturer since 2016, and was the Chair of IEEE ED/SSC Hong Kong Chapter (2017-2019). He is a recipient of the RGC Early Career Award in 2014, the Semiconductor Science and Technology Early Career Research Award in 2017, the PolyU FAST Faculty Award in Research and Scholar Activities in 2018/2019, the Young Scientist Award of ICON-2DMAT in 2019, the PolyU President’s Award in Research and Scholar Activities in 2019/2020, NR45 Young Innovators Award in 2021, Young Scientist of World Laureate Forum in 2021, and a finalist for the Falling Walls Science Breakthroughs of the Year 2022 in Engineering and Technology. His current research interest mainly focuses on emerging electronic devices.