Graphene/In2S3 van der Waals Heterostructure for Ultrasensitive Photodetection

As an emerging 2D nonlayered material, natural defective β-In2S3 nanosheets have drawn attention because of their unique defective structure and broad optical detection range. Stacking n-type In2S3 with other p-type 2D materials can produce an atomically sharp interface with van der Waals interaction, which may lead to high performance in (opto)electronics. In this study, we fabricated a van der Waals heterostructure composed of In2S3 and graphene via the dry transfer method. Scanning Kelvin probe force microscopy revealed a significant potential difference at the interface of the heterostructure, thereby endowing it with good diode characteristics. The back-gate field effect transistor based on the graphene/In2S3 heterostructure exhibited excellent gate-tunable current-rectifying characteristic with n-type semiconductor behavior. A photodetector based on the graphene/In2S3 heterostructure showed excellent response to visible light. Particularly, an ultrahigh responsivity of 795 A/W and an external quantu...