A light-emitting device comprises a substrate comprising a top surface; a plurality of light-emitting units formed on the top surface of the substrate comprising a first light-emitting unit, a second light-emitting unit, and one or a plurality of third light-emitting units, wherein each of the plurality of light-emitting units comprises a first semiconductor layer, an active layer and a second semiconductor layer; an insulating layer comprising a first insulating layer opening and a second insulating layer opening formed on each of the plurality of light-emitting units; a first extension electrode covering the first light-emitting unit, wherein the first extension electrode covers the first insulating layer opening on the first light-emitting unit without covering the second insulating layer opening on the first light-emitting unit; a second extension electrode covering the second light-emitting unit, wherein the second extension electrode covers the second insulating layer opening on the second light-emitting unit without covering the first insulating layer opening on the second light-emitting unit; a first electrode pad covering a part of the plurality of the light-emitting units; and a second electrode pad covering another part of the plurality of light-emitting units.