Self‐Filtering InGaN/GaN Multiple Quantum Wells Ultraviolet Photodetector With 12 nm Narrowband and 82 ns Ultrafast Response

Ultraviolet (UV) detection technology is critically important in fields such as environmental monitoring and communications. However, conventional photodetectors struggle to achieve both narrowband spectral response and ultrafast operational speed simultaneously. Herein, we demonstrate an InGaN/GaN multiple quantum wells UV photodetector architecture that surmounts this critical performance limitation by combining the concerted engineering of thin quantum wells, high heterojunction built‐in electric fields, and low‐capacitance microstructures. The device demonstrates exceptional filter‐free performance with a narrowband response at 365 nm, a full width at half maximum of <12 nm, and ultrafast rise/fall times of 82 and 89 ns, respectively, while achieving a dark current of 15 pA, external quantum efficiency of 14.6%, responsivity of 43.1 mA W −1 , and specific detectivity of 1.52 × 10 10 Jones at zero bias. The narrowband characteristic arises from intrinsic excitonic absorption in the quantum wells, while the ultrafast response stems from built‐in electric‐field‐driven rapid exciton dissociation and efficient charge collection enabled by the low‐capacitance design. Such devices provide an effective paradigm for high‐performance UV photodetectors, unlocking new application possibilities in biochemical sensing and high‐speed optical communications.