A Heterostructured Graphene Quantum Dots/β-Ga₂O₃ Solar-Blind Photodetector with Enhanced Photoresponsivity

The superior optical and electronic characteristics of quasi-two-dimensional β-Ga2O3 make it suitable for solar-blind (200–280 nm) photodetectors (PDs). The metal–semiconductor–metal (MSM) PDs commonly suffer from low photoresponsivity, slow response speed, and a narrow detection wavelength range despite their simple fabrication process. Herein, we report a high-performance MSM PD by integrating exfoliated β-Ga2O3 flakes with zero-dimensional graphene quantum dots (GQDs), which exhibits the advantages of enhancing the photoresponsivity, shortening the photoresponse time, and stimulating a broad range of photon detection. The hybrid GQDs/β-Ga2O3 heterostructure PD is sensitive to deep-ultraviolet (DUV) light (250 nm) with an ultrahigh responsivity (R of ∼2.4 × 105 A/W), a large detectivity (D* of ∼4.3 × 1013 Jones), an excellent external quantum efficiency (EQE of ∼1.2 × 108%), and a fast photoresponse (150 ms), which is superior to the bare β-Ga2O3 PD. These improvements result from effective charge transfer due to the introduction of GQDs, which enhance the light absorption and the generation of electron–hole pairs. In addition, the hybrid GQDs/β-Ga2O3 PD also exhibits better photoelectric performance than the bare β-Ga2O3 PD at a 1000 nm wavelength. As a conclusion, the hybrid GQDs/β-Ga2O3 DUV photodetector shows potential applications in commercial optoelectronic products and provides an alternative solution for the design and preparation of high-performance photodetectors.