Broadband Optical-Fiber-Compatible Photodetector Based on a Graphene-MoS2-WS2 Heterostructure with a Synergetic Photogenerating Mechanism

Integrating 2D crystals into optical fibers can grant them optoelectronic properties and extend their range of applications. However, the ability to produce complicated structures is limited by the challenges of chemical vapor deposition manufacturing. Here, a 2D-material heterostructure created on a fiber end-face is successfully demonstrated by integrating a microscale multilayer graphene-MoS2-WS2 heterostructure film on it, using a simple layer-by-layer transferring method. The all-in-fiber photodetector (FPD) exhibits an ultrahigh photoresponsivity of approximate to 6.6 x 10(7) A center dot W-1 and a relatively fast time response of approximate to 7 ms at 400 nm light wavelength, due to the strong light absorption and the built-in electric field of the heterostructure. Moreover, owing to the type-II staggered band alignments in the MoS2-WS2 heterostructure, the interlayer optical transition between the MoS2 and WS2 layers enables the FPD to sense the infrared light, displaying a photoresponsivity of approximate to 17.1 A center dot W-1 at 1550 nm. In addition, an inverse photoresponse is observed under high illuminating powers, indicating a competing photocurrent generation mechanism, comprising the photoconductive and photobolometric effects. It is believed that the findings will offer a new strategy for the development of novel all-fiber optoelectronic devices based on 2D crystals.