The invention discloses a silver-
germanium-
silicon heterogeneous hierarchical structure array, and a preparation method and an application of the array. The array is an array of
silicon micron hexagonal prisms in hexagonal arrangement, wherein the
silicon micron hexagonal prisms forming the array of silicon micron hexagonal prisms in hexagonal arrangement are provided with
germanium nanocones, surfaces of which is decorated with silver nanoparticles. The preparation method comprises: mixing a
nickel nitrate solution and an oxidized
grapheme solution to obtain a mixed liquid; immersing the array of silicon micron hexagonal prisms in hexagonal arrangement obtained via photoetching and deep
silicon etching technique in the mixed liquid to obtain the array of silicon micron hexagonal prisms, surfaces of which are decorated with
nickel nitrate, in hexagonal arrangement; then applying a
chemical vapor deposition method to enable the array of silicon micron hexagonal prisms, surfaces of which are decorated with
nickel nitrate, in hexagonal arrangement to be deposited with the
germanium nanocones; and immersing the array of silicon micron hexagonal prisms, surfaces of which are decorated with the germanium nanocones, in a
silver nitrate solution to obtain the target product. The silver-germanium-silicon heterogeneous hierarchical structure array can be used as an
active matrix of SERS, and is widely applicable to fast detection of the fields, such as environment,
chemistry, and
biology.