Hybrid mode for absorption enhancement in the Ga2O3 nanocavity photodetector with grating electrodes

Gallium oxide (Ga 2 O 3 ) photodetectors have drawn increased interest for their widespread applications ranging from military to civil. Due to the inherent oxygen vacancy defects, they seriously suffer from trade-offs that make them incompetent for high-responsivity, quick-response detection. Herein, a Ga 2 O 3 nanocavity photodetector assisted with grating electrodes is designed to break the constraint. The proposed structure supports both the plasmonic mode and the Fabry–Perot (F-P) mode. Numerical calculations show that the absorption of 99.8% is realized for ultra-thin Ga 2 O 3 (30 nm), corresponding to a responsivity of 12.35 A/W. Benefiting from optical mechanisms, the external quantum efficiency (EQE) reaches 6040%, which is 466 times higher than that of bare Ga 2 O 3 film. Furthermore, the proposed photodetector achieves a polarization-dependent dichroism ratio of 9.1, enabling polarization photodetection. The grating electrodes also effectively reduce the transit time of the photo-generated carriers. Our work provides a sophisticated platform for developing high-performance Ga 2 O 3 photodetectors with the advantages of simplified fabrication processes and multidimensional detection.