Patent ID: 7755101

Claim:
A semiconductor light emitting device comprising: a substrate; a plurality of n-type semiconductor layers supported by the substrate; an active layer of a gallium nitride compound semiconductor material, the active layer being supported by the plurality of n-type semiconductor layers; a plurality of p-type semiconductor layers supported by the active layer, wherein the plurality of p-type semiconductor layers includes a p-type first semiconductor layer of In x1 Al y1 Ga 1−x1−y1 N, wherein X1=0 and y1 =0.2, having a first bandgap energy, and having an internal tensile strain, a p-type second semiconductor layer of In x2 Al y2 Ga 1−x2−y2 N, wherein (0≦x2 ≦1, 0≦y2 ≦1), and having a second bandgap energy, smaller than the first bandgap energy, and a p-type third semiconductor layer located between the first semiconductor layer and the second semiconductor layer, of In x3 Al y3 Ga 1−x3−y3 N, wherein x3 =0.04 and y3 =0.18, and having a third bandgap energy smaller than the first bandgap energy and larger than the second bandgap energy, wherein the p-type second semiconductor layer is located farther from the active layer than is the p-type first semiconductor layer.