Simulation on high-performance Ga₂O₃ photodetectors with the synergism of nanohole and nanograting

The Sun serves as the primary source of ultraviolet radiation on Earth. The ultraviolet-C (UVC) with the wave length of 200-280 nm is strongly absorbed by atmospheric ozone, thereby establishing a naturally low-background-noise “solar-blind region”. Solar-blind ultraviolet (UV) photodetectors operating in this spectral range exhibit significant potential in applications such as flame detection, missile early warning systems, and ozone monitoring. With its ultra-wide bandgap of 4.7-4.9 eV, β-Ga₂O₃ has emerged as a highly promising material for such detectors. To further enhance device performance, this study introduces a dual-layer light-trapping architecture that incorporates surface nanopores and a bottom aluminum grating. Simulations conducted using the finite-difference time-domain (FDTD) method reveal that this composite structure achieves an absorption efficiency of 63.7% at a wavelength of 250 nm, representing a 247% improvement compared to unstructured devices. Additionally, the device’s responsivity increases from 0.55 A·W⁻¹ to 7.08 A·W⁻¹, with more than 50% responsivity retained even at incident angles as large as 60°, demonstrating exceptional angular robustness. These simulation results confirm the synergistic interaction between light-scattering enhancement from nanopores and plasmonic resonance in metal gratings, offering a robust theoretical foundation for the design and fabrication of high-performance Ga₂O₃-based solar-blind ultraviolet photodetectors.