The disclosed light emitting diode includes a substrate provided, at a surface thereof, with protrusions, a buffer layer formed over the entirety of the surface of the substrate, a first semiconductor layer formed over the buffer layer, an active layer formed on a portion of the first semiconductor layer, a second semiconductor layer formed over the active layer, a first electrode pad formed on another portion of the first semiconductor layer, except for the portion where the active layer is formed, and a second electrode pad formed on the second semiconductor layer. Each protrusion has a side surface inclined from the surface of the substrate at a first angle, and another side surface inclined from the surface of the substrate at a second angle different from the first angle.