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

• Jiayong Yang, cizhe fang, Tong-Zhou Li, yibo wang, Xiaoxi Li, Xiangyu Zeng, Liu Yan, Yue Hao, and Genquan Han
• received 03/22/2024; accepted 04/30/2024; posted 04/30/2024; Doc. ID 524563
• Abstract: Gallium oxide (Ga2O3) photodetectors have drawnincreased interest for their widespread applicationsranging from military to civil. Due to the inherent oxygenvacancy defects, they seriously suffer from trade-offs thatmake them incompetent for high-responsivity, quickresponse detection. Herein, a Ga2O3 nanocavityphotodetector assisted with grating electrodes isdesigned to break the constraint. The proposed structuresupports both the plasmonic mode and the Fabry-Pérot(F-P) mode. Numerical calculations show that theabsorption of 99.8% is realized for ultra-thin Ga2O3 (30nm), corresponding to a responsivity of 12.35 A/W.Benefiting from optical mechanisms, the externalquantum efficiency (EQE) reaches 6040%, which is 466times higher than that of bare Ga2O3 film. Furthermore,the proposed photodetector achieves a polarizationdependent dichroism ratio of 9.1, enabling polarizationphotodetection. The grating electrodes also effectivelyreduce the transit time of the photo-generated carriers.Our work provides a sophisticated platform fordeveloping high-performance Ga2O3 photodetectors withthe advantages of simplified fabrication processes andmultidimensional detection.