▎ 摘　　要

NOVELTY - Photodetector (10) comprises a first electrode, a collector layer (12) on the first electrode, a tunnel barrier layer (13) on the collector layer, a graphene layer (14) on the tunnel barrier layer, an emitter layer (15) on the graphene layer, and a second electrode on the emitter layer. The collector layer includes a first semiconductor material and the emitter layer includes a second semiconductor material, where at least one semiconductor material of the first semiconductor material and the second semiconductor material includes a transition metal dichalcogenide that is a compound of a transition metal and a chalcogen element that is one of sulfur (S), selenium (Se), or Te (tellurium). The emitter layer has a thickness of about 0.3 nanometer (nm) to about 1 micros (µm) such that the emitter layer absorbs light and moves electrons and holes, and where the tunnel barrier layer has a thickness of about 0.3 nm to about 1 µm. USE - Photodetector i.e., avalanche photodetectors for use in image sensor. ADVANTAGE - A photodetector has a small form factor and having high detection efficiency with respect to both visible light and infrared rays. The avalanche photodetectors are configured to utilize a photo-doping effect associated with graphene. The infrared photodetectors to be manufactured with a small form factor so that they can be applied to smartphones or wearable devices. DETAILED DESCRIPTION - An INDEPENDENT CLAIM is included for an image sensor, which comprises a substrate, an insulating layer on the substrate, a first photodetector on the insulating layer, the first photodetector including the photodetector, such that the insulating layer is between the substrate and a first electrode of the first photodetector, and the first electrode of the first photodetector is between the insulating layer and a collector layer of the first photodetector, and a second photodetector on the first photodetector, where the second photodetector includes a separate collector layer, a separate tunnel barrier layer on the separate collector layer, a separate graphene layer on the separate tunnel barrier layer, a separate emitter layer on the separate graphene layer, and a separate second electrode on the separate emitter layer. DESCRIPTION OF DRAWING(S) - The drawing shows a schematic cross-sectional view of an avalanche photodetector. 10Avalanche photodetector 12Collector layer 13Tunnel barrier layer 14Graphene layer 15Emitter layer