Ru Nanograting-Enhanced Ga₂O₃ Solar-Blind Photodetectors via Localized Surface Plasmon Resonance

Plasmonic nanoarray structures offer great potential for high-performance photodetectors due to their excellent ability to effectively trap light. In this work, Ga 2 O 3 solar-blind photodetectors with Ru nanogratings were designed, precisely fabricated, and characterized systematically for the first time. The Ru nanograting through localized surface plasmon resonance significantly concentrates the optical field, reduces the transmittance, and enhances light–matter interactions, ultimately increasing absorbance. Integrating the Ru nanograting into Ga 2 O 3 films induces a blue shift in the response peak, from 245 nm in Ga 2 O 3 films to 215 nm. Meanwhile, the peak current rises dramatically from 4.9 × 10 –11 to 1.3 × 10 –9 A. The peak responsivity and specific detectivity are increased by 4.9 × 10 2 times and 6.8 × 10 2 times, respectively. This modification also accelerates the response speed, with τ r and τ d, of 0.96/0.14 s, notably shorter than the 1.57/0.47 s in Ga 2 O 3 films. The mechanisms underlying strengthened absorbance and light–matter interactions are comprehensively explained through both simulated and experimental data. This work lays the theoretical and experimental groundwork for future high-performance Ga 2 O 3 -based photodetectors.