Exemplary embodiments of the present invention relate to a high-efficiency light emitting diode (LED). The LED according to an exemplary embodiment includes a substrate, a semiconductor stack arranged on the substrate, wherein the semiconductor stack has a p-type semiconductor layer, an active layer and an n-type semiconductor layer, a first metal layer interposed between the substrate and the semiconductor stack, the first metal layer ohmic-contacted with the semiconductor stack, a first electrode pad arranged on the semiconductor stack, an electrode extension extending from the first electrode pad, wherein the electrode extension has a contact region contacting the n-type semiconductor layer, a first insulating layer interposed between the substrate and the semiconductor stack, wherein the first insulating layer covers a surface region of the p-type semiconductor layer under the contact region of the electrode extension, and a second insulating layer interposed between the first electrode pad and the semiconductor stack.