▎ 摘　　要

NOVELTY - A graphene/aluminum trioxide/gallium arsenide terahertz photodetector comprises a substrate, which is a gallium arsenide substrate, an aluminum oxide insulating layer and a graphene layer, which are sequentially arranged on the upper surface of the N-type gallium arsenide substrate from bottom to top. A gallium arsenide layer, the aluminum trioxide insulating layer and the graphene layer are sequentially contacted to form a tunneling heterojunction. The photodetector further comprises an electrode (A) and a side electrode. The electrode (A) is arranged on the upper surface of the graphene layer, and has a ring structure. The side electrode is arranged on the bottom surface of the gallium arsenide layer. The area of the aluminum trioxide insulating layer is greater than 10% of the area of the gallium arsenide substrate and not greater than 100% of the area of the gallium arsenide layer. The area of the side electrode is 1-10% of the area of the gallium arsenide substrate. USE - Graphene/aluminum trioxide/gallium arsenide terahertz photodetector. ADVANTAGE - The terahertz photodetector optimizes its device performance through the tunneling effect of the heterojunction, has low dark state current, extremely high responsivity and detection degree to the terahertz band, and is simple. DETAILED DESCRIPTION - A graphene/aluminum trioxide/gallium arsenide terahertz photodetector comprises a substrate, which is a gallium arsenide substrate, an aluminum oxide insulating layer and a graphene layer, which are sequentially arranged on the upper surface of the N-type gallium arsenide substrate from bottom to top. A gallium arsenide layer, the aluminum trioxide insulating layer and the graphene layer are sequentially contacted to form a tunneling heterojunction. The photodetector further comprises an electrode (A) and a side electrode. The electrode (A) is arranged on the upper surface of the graphene layer, and has a ring structure. The side electrode is arranged on the bottom surface of the gallium arsenide layer. The area of the aluminum trioxide insulating layer is greater than 10% of the area of the gallium arsenide substrate and not greater than 100% of the area of the gallium arsenide layer. The area of the side electrode is 1-10% of the area of the gallium arsenide substrate. The area of the electrode (A) is smaller than the area of the graphene layer. The area of the graphene layer (3) is not larger than the area of the gallium arsenide substrate. An INDEPENDENT CLAIM is included for a method for preparing the graphene/aluminum trioxide/gallium arsenide terahertz photodetector.