Integrating Graphene/MoS₂ Heterostructure with SiN_x Waveguide for Visible Light Detection at 532 nm Wavelength

In this work, a silicon nitride waveguide-integrated photodetector based on a transferred graphene/MoS₂ heterostructure has been reported, where photo-generated electron–hole pairs are produced in the CVD-grown MoS₂ monolayer and rapidly separated at the heterostructure interface, followed by electrons continuously transferring to the graphene layer induced by an effective built-in electrical field. By tuning the back-gate voltage to control the Fermi-level in graphene layer, a competitive photoresponsivity of 440 mA W⁻¹ at 532 nm is achieved. Furthermore, these exhibit a photoresponse rate with a rise time of 80 ms and a fall time of 30 ms. It is believed that the 2D heterostructure has potentials for future applications in integrated optoelectronic circuits.