A highly sensitive, large area, and self-powered UV photodetector based on coalesced gallium nitride nanorods/graphene/silicon (111) heterostructure
Nur ‘Adnin Akmar Zulkifli, Kwangwook Park, Jung‐Wook Min, Boon S. Ooi, Rozalina Zakaria, Jongmin Kim, Chee Leong Tan
Abstract
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 μs (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.