The invention provides a single-
photon detector and a manufacturing method thereof, and a single-
photon detector array. The method comprises the steps of sequentially growing a plurality of epitaxial 
layers on one side of a provided substrate, and enabling the epitaxial 
layers to comprise a buffer layer, an 
absorption layer, a 
transition layer, a 
charge layer, a multiplication layer, an inversion layer, a migration layer, a window layer, and an 
ohmic contact layer, and forming an arc-shaped 
diffusion region in the 
ohmic contact layer and the window layer through a 
diffusion process, 
etching the edge of a part of the epitaxial layer on the substrate to form a mesa structure, forming an optical window on the back surface of the substrate, forming a P-type 
electrode on the 
ohmic contact layer, and forming an N-type 
electrode on the back surface of the substrate. According to the scheme, the edge 
electric field of the 
diffusion area can be effectively reduced only through one-time diffusion treatment and combination of the inversion layer, then the edge breakdown problem is effectively restrained, and compared with an existing mode needing secondary diffusion treatment or 
secondary growth, the complexity of the manufacturing process is effectively reduced.