A light-emitting device includes a semiconductor light-emitting stack; a current injected portion formed on the semiconductor light-emitting stack; an extension portion having a first branch radiating from the current injected portion and having a first width, and a first length greater than the first width, and a second branch extending from the first branch and having a second width larger than the first width, and a second length greater than the second width; and an electrical contact structure between the second branch and the semiconductor light-emitting stack.