Patent ID: 8586965

Claim:
A Group III nitride semiconductor light-emitting device comprising: at least an n-type-layer-side cladding layer; a light-emitting layer comprising a multiple quantum structure comprising a plurality of layer units, each unit comprising at least a well layer, a first barrier layer comprising Al x1 Ga 1-x1 N (0<x1<1), and a second barrier layer comprising Al x2 Ga 1-x2 N (0<x2<1) with an Al composition ratiox2 which is more than an Al composition ratio x1 of the first barrier layer; and a p-type-layer-side cladding layer, each of the n-type-layer-side cladding layer, the light-emitting layer, and the p-type-layer-side cladding layer comprising a Group III nitride semiconductor, wherein, the light-emitting layer comprises a first block, a second block, and a third block in a thickness direction from the n-type-layer-side cladding layer to the p-type-layer-side cladding layer, an Al composition ratio of a selected barrier layer which is at least one of the first barrier layer and the second barrier layer in each block is set to satisfy a relation z<y<x where an average Al composition ratio of the selected barrier layer(s) in the first block is represented as x, an average Al composition ratio of the selected barrier layer(s) in the second block is represented as y, and an average Al composition ratio of the selected barrier layer(s) in the third block is represented as z.