Programmable Micelle Templated Electrochemical Deposition Synthesis of Mesoporous Chalcogenide Semiconductors Thin Film for High‐Performance Photodetector

Surface topography serves as powerful tuning knobs for enhancing the performance of compound semiconductor‐based photodetectors. However, existing studies have been confined to microscale or submicron structures (e.g., photonic crystals) due to the challenges in fabricating well‐defined sub‐50 nm mesostructures in semiconductor thin films. Here, a programmable and scalable approach to synthesize mesoporous Bi 2 Se 3 (mBi 2 Se 3 ) films with precisely tunable pore size (13–30 nm), porosity, thickness, and crystallinity via amphiphilic block copolymer‐templated electrochemical deposition is presented. The resulting nanoscale spherical interfaces enable multi‐level light scattering, significantly boosting photodetector performance. The mBi 2 Se 3 /Au/Si based optimized devices exhibit a responsivity (R) of 6 mA W −1 , a detectivity (D*) of 10 13 Jones, and a sensitivity ( S ) of 10 6 cm 2 /W—orders of magnitude higher than their non‐porous counterparts, and superior to other reported Bi 2 Se 3 based or mesostructured photodetectors. This work advances optical micro/nanostructure engineering down to the 10‐nm scale, paving the way for next‐generation photodetectors that simultaneously achieve high responsivity, detectivity, and speed. These findings hold great promise for applications in high‐resolution infrared imaging and real‐time image recognition.