Yin Lanxin, Wang Xiaoyue, Feng Shun
College of Information Science and Engineering, Northeastern University, Shenyang 110819, China.
Shenyang National Laboratory for Materials Science, Institute of Metal Research, Chinese Academy of Sciences, 72 Wenhua Road, Shenyang 110016, China.
Nanomaterials (Basel). 2025 Aug 3;15(15):1190. doi: 10.3390/nano15151190.
Graphene's exceptional carrier mobility and broadband absorption make it promising for ultrafast photodetection. However, its low optical absorption limits responsivity, while the absence of a bandgap results in high dark current, constraining the signal-to-noise ratio and efficiency. Although silicon (Si) photodetectors normally offer fabrication compatibility, their performance is severely hindered by interface trap states and optical shading. To overcome these limitations, we demonstrate an epitaxial graphene/n-Si heterojunction photodiode. This device utilizes graphene epitaxially grown on germanium integrated with a transferred Si thin film, eliminating polymer residues and interface defects common in transferred graphene. As a result, the fabricated photodetector achieves an ultralow dark current of 1.2 × 10 A, a high responsivity of 1430 A/W, and self-powered operation at room temperature. This work provides a strategy for high-sensitivity and low-power photodetection and demonstrates the practical integration potential of graphene/Si heterostructures for advanced optoelectronics.
石墨烯卓越的载流子迁移率和宽带吸收特性使其在超快光电探测方面颇具潜力。然而，其低光吸收率限制了响应度，而缺乏带隙则导致暗电流较高，从而限制了信噪比和效率。尽管硅（Si）光电探测器通常具有制造兼容性，但其性能受到界面陷阱态和光学遮蔽的严重阻碍。为克服这些限制，我们展示了一种外延石墨烯/n-Si异质结光电二极管。该器件利用外延生长在锗上的石墨烯与转移的Si薄膜集成，消除了转移石墨烯中常见的聚合物残留和界面缺陷。结果，所制备的光电探测器实现了1.2×10 A的超低暗电流、1430 A/W的高响应度以及室温下的自供电运行。这项工作为高灵敏度和低功耗光电探测提供了一种策略，并展示了石墨烯/Si异质结构在先进光电子学中的实际集成潜力。
