Nitride semiconductor light-emitting device

A nitride semiconductor light-emitting device comprising:

• a nitride semiconductor substrate including a main surface having an off angle of 0.4° to 5° with respect to a (0001) plane;
• a first semiconductor layer formed of an n-type or p-type AlGaN or AlInGaN formed on the main surface of the nitride semiconductor substrate;
• a second semiconductor layer formed of a nitride semiconductor having In composition of 2% or higher formed on the first semiconductor layer;
• an active layer formed on the second semiconductor layer including a well layer formed of a nitride semiconductor having In composition higher than the In composition of the second semiconductor layer and a barrier layer formed of a nitride semiconductor stacked therein;
• a third semiconductor layer formed on the active layer having a conductivity type different from the conductivity type of the first semiconductor layer;
• and
• a fourth semiconductor layer formed between the main surface of the nitride semiconductor substrate and the first semiconductor layer, and formed of a nitride semiconductor having In composition of 2% or higher, the In composition lower than the In composition of the well layer, wherein
• the first semiconductor layer has a lower In composition than the fourth semiconductor layer.