A semiconductor device comprises: a first semiconductor structure; a second semiconductor structure on the first semiconductor structure; an active region, wherein the active region comprises multiple alternating well layers and barrier layers, the active region further comprises an upper surface facing the second semiconductor structure and a bottom surface opposite the upper surface; an electron blocking region between the second semiconductor structure and the active region; a first aluminum-containing layer between the electron blocking region and the active region, wherein the first aluminum-containing layer has a band gap greater than the band gap of the first electron blocking layer; and a p-type dopant above the bottom surface of the active region and comprising a concentration profile comprising a peak shape having a peak concentration value, wherein the peak concentration value lies at a distance of between 15 nm and 60 nm from the upper surface of the active region.