Patent ID: 7756177

Claim:
A semiconductor light-emitting device comprising: a substrate; and a plurality of III-V compound semiconductor layers supported by said substrate, each layer containing at least Ga and N as principal constituents, wherein said plurality of compound semiconductor layers include, sequentially arranged, a first cladding layer of a first conductivity type, said first cladding layer including a plurality Al x Ga 1-x N (0≦x≦1) layers in which x increases toward said substrate, each of said Al x Ga 1-x N layers having a respective refractive index, an active layer with a multi-quantum-well structure that includes at least two InGaN well layers, said first cladding layer being interposed between said substrate and said active layer, and a second cladding layer of a second conductivity type, opposite the first conductivity type and disposed on an opposite side of said active layer from said first cladding layer, said second cladding layer having a refractive index, wherein said light-emitting device has a light confinement coefficient in a range from 1.5% to 2.0%, the light confinement coefficient indicating proportion of light in said at least two InGaN well layers to overall waveguide light in said light-emitting device during light emission by said light-emitting device.