Light-Speed Up: How Graphene Boosts Photodetectors

Photodetectors play a crucial role in tools like high-speed communication systems and real-time monitoring devices. But many current photodetectors face challenges like low carrier efficiency and slow response times due to material constraints and interface mismatches. In this study, researchers designed a unique sandwich structure called the WS2/Graphene/MoS2 vertical van der Waals heterojunction. They made it using mechanical exfoliation and dry transfer techniques to tackle these issues. To speed up the device, the team added graphene between layers of WS2 and MoS2. Graphene's high mobility and smooth surface helped improve carrier transport efficiency and reduced interface defects. When tested with a 405 nm laser and a 0. 5V bias, the device showed impressive speeds with rise and fall times of 44 and 52 microseconds. At 2. 5V bias, the device also demonstrated excellent performance, including high responsivity (220 A/W), notable detectivity (1. 2 x 10^13 Jones), significant external quantum efficiency (6. 7 x 10^4 %), and a low dark current (1. 05 x 10^-13 A). These results open the door for fast and reliable optical communication systems. This innovative design could change how we think about creating high-performance photodetectors, making them faster and more efficient.

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