Broadband Photodetection and On-Chip Convolution Computing Based on PdSe₂/Si van der Waals Heterojunction Arrays

Palladium diselenide (PdSe₂), a two-dimensional noble metal dichalcogenide, has recently emerged as a highly promising material for intelligent optoelectronics due to its layer-dependent bandgap tunability, high carrier mobility, and intrinsic in-plane anisotropy. However, current PdSe₂-based photodetectors are largely limited to single-pixel architectures, which fundamentally constrain their capabilities for spatially resolved sensing and on-chip information processing. In this work, we propose an in situ growth PdSe₂/Si van der Waals heterojunction photodetector array that integrates broadband photodetection, polarization imaging, and in-sensor optical computing within a unified and scalable platform. Benefiting from the strong built-in electric field at the heterointerface, the device exhibits excellent self-powered photoresponse over a broad spectral range from 375 to 1550 nm, achieving a responsivity of 203.89 mA/W and a specific detectivity of 3.3 × 10¹¹ Jones at the infrared band. Under zero-bias operating conditions, real-time optical transmission of ASCII information is successfully demonstrated at 1310 nm. In addition, benefiting from the intrinsic anisotropic absorption of PdSe₂, the heterojunction device enables polarization-resolved imaging with a decent anisotropy ratio. Leveraging on the programmable pixel biasing, edge extraction and image sharpening are directly realized within the PdSe₂/Si heterojunction array, providing a promising pathway toward in-sensor computing and integrated intelligent optoelectronic systems.