High-Responsivity UV Photodetectors Based on High-Mobility Graphene Epitaxially Grown on 4H-SiC

Achieving outstanding detection performance with a simple detector construction has long been one of the goals of photodetector development. In this study, we report a high-responsivity graphene/silicon carbide (Gr/SiC) ultraviolet (UV) photodetector consisting of a monolayer of graphene grown epitaxially on the silicon surface of SiC. By optimizing the growth process, the carrier mobility of the monolayer graphene with a large area of 3.5 × 4.5 mm 2 was achieved up to 3020.54 cm 2 /(V·s). Under UV irradiation of 0.004 μW at 275 nm, the Gr/SiC photodetector achieves a high responsivity of 5425 A/W, which is 1 order of magnitude higher than the 254.1 A/W of the best responsivity of reported Gr/SiC UV detectors. Meanwhile, the photoconductive gain of the photodetector reaches 24462, which is nearly 50 times the highest photoconductive gain of 490.8 among reported Gr/SiC UV detectors. This outstanding performance is driven by the excellent carrier mobility of the epitaxial graphene, which enables the photogenerated carriers to rapidly migrate to the electrodes, thus significantly improving the photoconductive gain of the detector. At the same time, the simplified preparation process greatly reduces the cost, shortens the production cycle, and improves the feasibility of mass production, which provides crucial support for the industrial application of high-responsivity UV photodetectors.