Abstract: The invention relates to a wide spectrum multi-band detection structure with selective absorption enhancement and its preparation method. The structure comprises a plurality of sub-pixel units capable of detecting incident light in different bands. Each sub-pixel unit is composed of a square well-shaped microstructure array and a metal lower electrode (2), a photosensitive layer (3) and an upper electrode (4) on the surface thereof. The size and array spacing of square well-shaped microstructures in different sub-pixel units are determined according to the detection bands of the sub-pixel units where they are located. The upper openings of the square well-shaped microstructures are hollow to form a resonant cavity, and the adjacent square well-shaped microstructures in the same sub-pixel unit form a resonant cavity, thus solving the problem that the detector structure in the prior art cannot simultaneously realize visible light-near infrared multi-band absorption enhancement detection.

Abstract: A photodetector based on PtSe2 and a silicon nanopillar array includes a PMMA light-transmitting protective layer, a graphene transparent top electrode, a silicon nanopillar array structure coated with few-layer PtSe2, and metal electrodes of the graphene transparent top electrode and the silicon nanopillar array structure. A method for preparing the photodetector includes steps of: preparing graphene with a CVD method; preparing a silicon nanopillar array structure through dry etching; coating few-layer PtSe2 on surfaces of the silicon nano-pillar array structure through laser interference enhanced induction CVD; preparing graphene transparent top electrode; and magnetron-sputtering metal electrodes. The photodetector prepared by the present invention has a detection range from visible light to near-infrared wavebands. The silicon nanopillar array structure enhances light absorption of the detector, so that the detector has high sensitivity, simple structure and strong practicability.