| 摘要 |
An avalanche photodiode includes: a P-type contact layer (11), a light absorption layer (12), a compositionally-graded symmetrical multiplication layer (13), and an N-type contact layer (14). The P-type contact layer (11) is connected to the light absorption layer (12), the light absorption layer (12) is connected to the compositionally-graded symmetrical multiplication layer (13), and the compositionally-graded symmetrical multiplication layer (13) is connected to the N-type contact layer (14). The compositionally-graded symmetrical multiplication layer (13) is configured to amplify the electrical signal, and the compositionally-graded symmetrical multiplication layer (13) has a centrosymmetric structure and includes multiple graded layers. In the technical solution, multiple graded layers are used to suppress ionization of a carrier so as to reduce an excess noise factor, and the symmetrical structure of the compositionally-graded symmetrical multiplication layer (13) effectively relaxes a large stress of a lattice mismatched system, thereby obtaining a high-quality epitaxy film, and reducing noise. |
