Semiconductor device

A semiconductor device includes: a first semiconductor structure; a second semiconductor structure on the first semiconductor structure; an active region between the first semiconductor structure and the second semiconductor structure, wherein the active region comprises a well layer and a barrier layer, wherein the barrier layer has a band gap; a first electron blocking layer between the second semiconductor structure and the active region, wherein the first electron blocking layer comprises a band gap which is greater than the band gap of the barrier layer; a first aluminum-containing layer between the first electron blocking layer 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; a confinement layer between the first aluminum-containing layer and the active region; and a second aluminum-containing layer between the second semiconductor structure and the first electron blocking layer; wherein both the first alumi