Reconfigurable Floating‐Gate van der Waals Phototransistor With Asymmetric Contact Geometries for Bio‐Inspired Multi‐Stage Visual Tasks

Bio‐inspired optoelectronic devices with in‐sensor neuromorphic computing capability are promising for artificial visual applications. However, the biological visual system possesses simultaneous sensing and multi‐stage processing capability through the retina and visual cortex. Different device types and materials are required to emulate specific visual functions, which will unavoidably pose complexity in integration and limit the scalability. Herein, we report a WSe 2 /h‐BN/Graphene reconfigurable floating‐gate van der Waals phototransistor (RFGPT) featuring a laterally asymmetric contact geometry. The device exhibits reconfigurable optoelectronic functionality via gate voltage modulation, including photodetection mode with bipolar photoresponse and optoelectronic synapse mode with short‐term memory. The RFGPT fulfills versatile neuromorphic image processing functions, including retina‐level pre‐processing (edge extraction) and cortex‐level processing (image recognition). The RFGPT provides a fundamental unit to develop artificial visual hardware with reduced fabrication complexity and enhanced scalability for efficient in‐sensor computing.