▎ 摘　　要

NOVELTY - The photodetector has an insulating layer-I (2), a graphene-I (3) and a quantum dot-I (5) that are arranged from bottom to top. Two electrodes-I (4) are respectively arranged on two sides of the quantum dot-I. The quantum dot-I is provided with a dielectric layer (6), a graphene-II (7), a quantum dot-II (9), and an insulating layer-II (10). Two electrodes-II (8) are respectively arranged on two sides of the quantum dot-II. The quantum dot-I and the quantum dot-II are respectively fabricated using two quantum dot materials. A metal substrate (1) for applying a gate voltage is arranged under the insulating layer-I. A thickness of the insulating layer-I and the insulating layer-II is 100 to 1000 nm, and a thickness of the dielectric layer is 1 to 500 nm. USE - Composite structure-based graphene-quantum dot two-color photodetector for multi-color light detection. ADVANTAGE - The structure provides a reliable guarantee for the realization of infrared two-color, multi-color high-sensitivity detectors. The metal substrate, the insulating layer-I and the graphene-I are used as the resonant cavity of the microcavity structure, and the light is reflected multiple times between the insulating layer-I, which greatly improves the utilization of incident light. The responsiveness of the device is greatly improved, and the ability to detect weak energy photons is realized. The material and thickness of the insulating layer-I, the insulating layer-II and the dielectric layer can be selected in accordance with the requirements for light transmittance and dielectric constant. DETAILED DESCRIPTION - An INDEPENDENT CLAIM is included for a method for preparing the composite structure-based graphene-quantum dot two-color photodetector. DESCRIPTION OF DRAWING(S) - The drawing shows a front view illustrating the graphene-quantum dot two-color photodetector. Metal substrate (1) Insulating layer-I (2) Graphene-I (3) Two electrodes-I (4) Quantum dot-I (5) Dielectric layer (6) Graphene-II (7) Two electrodes-II (8) Quantum dot-II (9) Insulating layer-II (10)