Gate-Tunable Polarity-Reconfigurable Photovoltaic Response With Dual Linearity in NbS₃/WSe₂ Heterostructures for...

Reconfigurable optoelectronic image sensors capable of in-sensor computing are promising for energy-efficient edge visual perception. Self-powered photovoltaic operation further reduces the power demand of image sensing and processing. However, it remains challenging to achieve a continuously gate-tunable self-powered photovoltaic response that combines reversible polarity with linear weight programmability. Here, we demonstrate a gate-tunable photovoltaic detector based on an NbS₃/WSe₂ van der Waals heterostructure. Owing to the ambipolar transport of WSe₂ and the distinct electrostatic responses of the two constituent materials, gate voltage continuously modulates the interfacial band alignment and reversibly switches the built-in electric field at the heterointerface. Consequently, the device exhibits gate-controlled positive and negative photovoltaic responses. The short-circuit photocurrent scales linearly with incident power density, while the short-circuit photoresponsivity varies linearly with gate voltage over a broad programming window. This dual linearity allows the photoresponsivity to function as a programmable analog weight for in-sensor convolution. As a proof of concept, several image convolution kernels are implemented for in-sensor image processing, and the experimentally obtained outputs agree well with algorithmic simulations. This work provides a promising device-level building block for reconfigurable and energy-efficient vision sensors for edge computing.