Abstract: A light-emitting device is disclosed, including a light-emitting element and a surface plasmon coupling element, having an intermediary layer connected to the light-emitting element and a metal structure on the intermediary layer, wherein the intermediary layer is conductive under low-frequency injection current and has the characteristics as dielectric material in a wavelength range 100 nm˜20000 nm.

Abstract: The invention provides a light-emitting device, comprising a light-emitting element and a surface plasmon coupling element connected to the light-emitting element. In an embodiment of the invention, the surface plasmon coupling element comprises a dielectric layer connected to the light-emitting element and a metal layer on the dielectric layer. In another embodiment of the invention, the light-emitting device is a light-emitting diode, comprising an active layer between an n-type semiconductor layer and a p-type semiconductor layer, and a surface plasmon coupling element adjacent to the n-type semiconductor layer. In a further embodiment of the invention, a current spreading layer on a second type semiconductor layer of the light-emitting device includes a plurality of strip-shaped structures, and the surface plasmon coupling element is disposed on the current spreading layer and filled into the gap between the strip-shaped structures of the current spreading layer.