Patent ID: 8648348

Claim:
A light emitting device including: a substrate that has protrusions on a C-face, and of which unit cells are constructed in a hexagonal structure, wherein the substrate has flat surfaces between the protrusions; a semiconductor layer that is formed on the substrate, in which empty spaces are formed in sides of the protrusions, and of which unit cells are constructed in a hexagonal structure; and a light emitting structure layer including a first conductive semiconductor layer, a second conductive semiconductor layer and an active layer formed between the first conductive semiconductor layer and the second conductive semiconductor layer that are formed on the semiconductor layer, wherein an A-face of the substrate and an A-face of the semiconductor layer form an angle of greater than zero degree, and the protrusions include the R-faces, and wherein the empty spaces are disposed in a boundary region between the protrusion and the flat surface.