Infrared detector with photonic crystal over absorption layer and preparation method therefor

A short-wave infrared detector unit device, comprising a substrate, and an epitaxial layer arranged on a surface of the substrate, wherein an outermost layer of the epitaxial layer is an absorption layer (9);

• wherein the short-wave infrared detector unit device further comprises a photonic crystal structure layer arranged on a surface of the absorption layer (9), the photonic crystal structure layer is a third dielectric material layer (3) with a through-hole structure, the third dielectric material layer (3) has a refractive index of n3;
• the through-hole structure comprises first through holes (1) in periodic arrangement and second through holes (2) in periodic arrangement;
• each of the first through holes (1) is filled with a first dielectric material, the first dielectric material has a refractive index of n1;
• each of the second through holes (2) is filled with a second dielectric material, and the second dielectric material has a refractive index of n2, wherein n1 is less than n3, and n2 is less than n3;
• wherein a periodic arrangement rule of the first through holes (1) is that:
• a center of any of the first through holes (1) is taken as a center of a first regular hexagon, a side length of the first regular hexagon is La, and six vertexes of the first regular hexagon correspond to centers of other six first through holes (1), respectively;
• and
• a periodic arrangement rule of the second through holes (2) is that:
• the third dielectric material layer (3) is divided into a plurality of rectangular regions with a center of one of the first through holes (1) as a center of one of the plurality of rectangular regions, a length×width of each of the plurality of rectangular regions is 8 La×6.92 La, the plurality of rectangular regions do not overlap each other, the center of each of the plurality of rectangular regions is taken as a center of a second regular hexagon, a side length of the second regular hexagon is 2 La, and six vertexes of the second regular hexagon correspond to centers of the second through holes (2);
• wherein n1, n2, n3, La, a diameter Da of each of the first through holes (1), and a diameter Db of each of the second through holes (2) are set as follows:
• a) n1 is 1.46, n2 is 1.7, n3 is 4.0, La is 0.8 μm, Da is 0.6 μm, and Db is 0.2 μm;
• or
• b) n3 is 4.0, n2 is 1.7, n1 is 1.46, La is 0.7 μm, Da is 0.5 μm, and Db is 0.2 μm;
• or
• c) n3 is 3.47, n2 is 2.29, n1 is 1.46, La is 0.8 μm, Da is 0.6 μm, and Db is 0.4 μm, and wherein the third dielectric material layer (3) is made of a silicon material, the second dielectric material is a zinc sulfide material, and the first dielectric material is an amorphous silicon dioxide material.