Ultrahigh Sensitivity Solar‐Blind UV Detection via Multistage‐Concentric‐Annulus Architecture Metasurface

Abstract High‐sensitivity photodetection capability has become an indispensable requirement for detecting feeble solar‐blind ultraviolet (UV) light. Micro‐nano metallic metasurface structures are employed to enhance the detector photoelectric performances. However, existing approaches are confronted with bottlenecks of structure simplification and efficacy mediocrity. Here, a distinctive diamond solar‐blind UV photodetector with a synthetic multistage‐concentric‐annulus (MCA) architecture metasurface is reported, which is prepared through a facile and peculiar Fraunhofer diffraction technique. The detector achieves an excellent photo‐to‐dark‐current ratio of 2.4×10⁸ and maintains an extremely low dark current on the order of pA magnitude. The intrinsic response peak and resonance absorption phenomenon in solar‐blind UV are evident from the optical properties. Moreover, the surface potential distribution intuitively reveals that plasmon resonance enhances the UV scattering and absorption cross sections, thus facilitating the photogeneration of carriers. Meanwhile, it expressly demonstrates that multi‐level dipole interaction in the MCA structure accelerates the separation and extraction of electron–hole pairs through enhancing the localized electric field intensity. In addition, a wide range of variable temperature measurements further prove the device possesses capacity for working in extreme environments. This photodetection technology by virtue of a delicate and viable diffraction metasurface is anticipated to provide a leap forward for future applications in wide‐band‐gap semiconductor UV detectors.