A light-emitting device includes a first conductive semiconductor layer formed on a substrate, a mask layer formed on the first conductive semiconductor layer and having a plurality of holes, a plurality of vertical light-emitting structures vertically grown on the first conductive semiconductor layer through the plurality of holes, a current diffusion layer surrounding the plurality of vertical light-emitting structures on the first conductive semiconductor layer, and a dielectric reflector filling a space between the plurality of vertical light-emitting structures on the current diffusion layer.