An embodiment of present invention discloses a light-emitting device comprising a first multi-layer structure comprising a first lower layer; a first upper layer; and a first active layer able to emit light under a bias voltage and positioned between the first lower layer and the first upper layer; a second thick layer neighboring the first multi-layer structure; a second connection layer associated with the second thick layer; a connective line electrically connected to the second connection layer and the first multi-layer structure; a substrate; and two or more ohmic contact electrodes between the first multi-layer structure and the substrate.