Anisotropic Ga ₂ O ₃ Nanograting with Photonic and Band Engineering Enables High‐Sensitivity Solar‐Blind Photodetectors

Abstract Ga2O3‐based solar‐blind UV photodetectors exhibit intrinsic solar‐blind absorption and radiation tolerance but remain limited by surface leakage current, inefficient photon‐carrier coupling, and weak polarization sensitivity. Herein, a nanograting photonic structure is introduced to modulate carrier dynamics through photonic and band engineering. This design strengthens photon‐carrier coupling and tunes interfacial energy band structure to enhance photoconductive gain and suppress dark current. Nanograting structure effectively reduces dark current through an upshifted interfacial conduction band, while simultaneously intensifying light absorption via reduced reflectance and transmittance. Its inherent anisotropy enables polarization discrimination without external optics or phase tuning approaches. The optimized device achieves an ultra‐low dark current of 1.8 × 10 ⁻¹⁴ A, a responsivity of 174.8 A W ⁻¹ , a specific detectivity of 1.7 × 10 ¹⁴ Jones (a 1209.3% improvement), and a high polarization ratio of 570%, remarkably surpassing planar Ga2O3 solar‐blind photodetectors (SBPDs). This work demonstrates a novel strategy through photonic‐electronic integration for high‐sensitivity, low‐noise SBPDs with excellent polarization response.