Epitaxial growth of bilayer MoS2/MoSe2 heterostructure with high-responsivity enhanced by photogating effect

Van der Waals (vdW) semiconductors heterostructure based on transition metal dichalcogenides (TMDs) is a promising candidate for two-dimensional (2D) ultra-thin optoelectronic devices due to the strongly interlayer coupling and efficient carrier separation. However, the directly epitaxial growth of 2D TMDs vdW heterostructures with a clean interface and high photoresponsivity still remains a challenging. In this work, the epitaxial growth of bilayer MoS2/MoSe2 vdW heterostructure with atomic-layer clean interface is prepared via an iodine-assisted growth strategy. The electrical properties and optoelectronic characterization proves that the heterostructure device presents an enhanced photoresponsivity of 680 A/W, indicting the 21.25 times higher compared with pure MoS2, which benefited from the photogating effect formed by the localized electrons in this heterostructure. This study offers a well reference for the controlled growth of the TMDs vdW heterostructure, and the achieved heterostructure will prove promising applications in future integrated optoelectronic devices and systems.