In this paper, we demonstrate an ultraviolet photodetector (UV-PD) that uses coalesced gallium nitride (GaN) nanorods (NRs) on a graphene/Si (111) substrate grown by plasma-assisted molecular beam epitaxy. We report a highly sensitive, self-powered, and hybrid GaN NR/graphene/Si (111) PD with a relatively large 100 mm2 active area, a high responsivity of 17.4 A/W, a high specific detectivity of 1.23 1013 Jones, and fast response speeds of 13.2/13.7 ls (20 kHz) under a UV light of 355 nm at zero bias voltage. The results show that the thin graphene acts as a perfect interface for GaN NRs, encouraging growth with minimum defects on the Si substrate. Our results suggest that the GaN NR/graphene/Si (111) heterojunction has a range of interesting properties that make it well-suited for a variety of photodetection applications.
Bibliographical noteKAUST Repository Item: Exported on 2020-11-16
Acknowledgements: The authors extend special thanks to Dr. Mohammad Khaled Shakfa and Ram Chandra Subedi of the Photonics Laboratory, King Abdullah University of Science and Technology, Saudi Arabia, for their useful discussions and PL measurement. The authors declare that they have no competing financial interest. R. Zakaria and N. A. A. Zulkifli would like to acknowledge support from the University of Malaya (No. IIRG03–2019). K. Park would like to acknowledge support from the National Research Foundation of Korea (NRF) grant funded by the Korea Government (MSIT) (No. NRF2020R1F1A1070471).