▎ 摘　　要

NOVELTY - The photodetector (300) has a waveguide (320) on a substrate (310). A photo detection portion (330) is configured to receive light incident on the waveguide. The photo detection portion includes one semiconductor layer which is an epitaxially grown silicon layer that contacts the waveguide. A graphene (333) is placed on the one semiconductor layer. Other semiconductor layer which is a polysilicon layer is placed on the graphene. Two insulation layers (332,334) are provided between the two semiconductor layer and the graphene respectively. USE - Photodetector e.g. waveguide-integrated graphene photodetector. ADVANTAGE - The higher speed operation in the photo detector can be enabled by forming the photo detector in contact with the waveguide and graphene in the photo detector so as to move electrons using the graphene. The deterioration of mobility of the graphene can be suppressed when the two insulation layers are formed of hexagonal boron nitride. The leakage of light in the photodetector can be reduced so the coupling efficiency of graphene and light can be improved. The light detection efficiency can be improved. The graphene in the photo detection portion increases light absorption rate so the sensitivity of the photo detector can be improved. DESCRIPTION OF DRAWING(S) - The drawing shows a sectional perspective view of the photo detector. Photodetector (300) Substrate (310) Waveguide (320) Photo detection portion (330) Insulation layers (332,334) Graphene (333)