A method includes steps of: sequentially growing a first semiconductor layer of a first conductivity type, an active layer, and a second semiconductor layer of a second conductivity type on a growth substrate to form a layered structure; separating the substrate from the layered structure to expose the first layer; performing wet etching on an exposed surface to form defect depressions; forming an insulating layer on the exposed surface; polishing the insulating layer and the first layer to flatten the surface of the first layer; and performing wet etching on the surface of the first layer to form protrusions deriving from a crystal structure.