US Patent 7511307 Light emitting device

A light emitting device includes: a light-enhancing layered structure of a hexagonal crystal system, the light-enhancing layered structure including a light-enhancing layer having a planar surface that is formed with a plurality of light-enhancing units thereon, each of the light-enhancing units extending in a normal direction relative to the planar surface, being tapered from the planar surface, and having three inclined faces that are adjoined side-by-side and that are respectively parallel to corresponding symmetrical ones of the crystal planes {11 2 k} of the hexagonal crystal system, where k=2 to 5; and a light emitting layered structure formed on the light-enhancing layered structure.