A light emitting device comprising: a support substrate; a wafer bonding layer (130, 170) over the support substrate; a second electrode layer including a current blocking layer and a reflective current spreading layer over the wafer bonding layer (130, 170); a current injection layer over the second electrode layer; a superlattice structure layer over the current injection layer; a second conductivity type semiconductor layer over the superlattice structure layer; an active layer over the second conductivity type semiconductor layer; a first conductivity type semiconductor layer over the active layer; a light extracting structure layer on the first conductivity type semiconductor layer; a first ohmic contact electrode layer on the first conductivity type semiconductor layer and the light extracting structure layer; a first electrode layer on the first ohmic contact electrode layer; wherein the light extracting structure layer comprises a first concavo-convex structure on the first conductive semiconductor layer, wherein the first ohmic contact electrode layer is disposed on a top surface of the light extracting structure layer, wherein a bottom surface of the first ohmic contact electrode layer comprises a second concavo-convex structure corresponding to the first concavo-convex structure of the light extracting structure layer, wherein the current blocking layer is disposed on the wafer bonding layer (130, 170) and is extended to the superlattice structure layer, and. wherein the reflective current spreading layer is disposed on the current blocking layer and a portion of the reflective current spreading layer passes through the superlattice structure layer. a support substrate; a wafer bonding layer (130, 170) over the support substrate; a second electrode layer including a current blocking layer and a reflective current spreading layer over the wafer bonding layer (130, 170); a current injection layer over the second electrode layer; a superlattice structure layer over the current injection layer; a second conductivity type semiconductor layer over the superlattice structure layer; an active layer over the second conductivity type semiconductor layer; a first conductivity type semiconductor layer over the active layer; a light extracting structure layer on the first conductivity type semiconductor layer; a first ohmic contact electrode layer on the first conductivity type semiconductor layer and the light extracting structure layer; a first electrode layer on the first ohmic contact electrode layer; wherein the light extracting structure layer comprises a first concavo-convex structure on the first conductive semiconductor layer, wherein the first ohmic contact electrode layer is disposed on a top surface of the light extracting structure layer, wherein a bottom surface of the first ohmic contact electrode layer comprises a second concavo-convex structure corresponding to the first concavo-convex structure of the light extracting structure layer, wherein the current blocking layer is disposed on the wafer bonding layer (130, 170) and is extended to the superlattice structure layer, and. wherein the reflective current spreading layer is disposed on the current blocking layer and a portion of the reflective current spreading layer passes through the superlattice structure layer.