Ultraviolet-infrared dual-color photodetector based on vertical GaN nanowire array and graphene

A monolithic integrated ultraviolet-infrared (UV-IR) dual-color photodetector based on graphene/GaN heterojunction was fabricated by vertically integrating a GaN nanowire array on a silicon substrate with monolayer graphene. The device detects UV and IR lights by different mechanisms. The UV detection is accomplished by the forbidden band absorption of GaN, and the IR detection is realized by the free electron absorption of graphene. At peak wavelengths of 360 nm and 1540 nm, the detector has responsivities up to 6.93 A/W and 0.11 A/W, detection efficiencies of 1.23 × 1012 cm·Hz1/2 ·W−1 and 1.88 × 1010 cm·Hz1/2 ·W−1, respectively, and a short response time of less than 3 ms.