Nitride semiconductor light-emitting device
A nitride semiconductor light-emitting device having high luminous efficiency is provided. A nitride semiconductor light-emitting device is provided with a nitride semiconductor substrate including a main surface having an off angle of 0.4° or larger with respect to a (0001) plane, a first semiconductor layer formed of an n-type or p-type nitride semiconductor formed on the main surface, 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 that of the second semiconductor layer and a barrier layer formed of a nitride semiconductor stacked therein, and a third semiconductor layer formed on the active layer having a conductivity type different from that of the first semiconductor layer.
1. 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.
2. The nitride semiconductor light-emitting device according to claim 1 , wherein
the off angle is 0.5° to 1.0°.
3. The nitride semiconductor light-emitting device according to claim 1 , wherein
the second semiconductor layer has a thickness of 100 nm or larger.
4. The nitride semiconductor light-emitting device according to claim 1 , wherein
the second semiconductor layer includes a surface which is in contact with the active layer.
5. The nitride semiconductor light-emitting device according to claim 1 , wherein
the nitride semiconductor substrate includes the main surface inclined in a <1-100> direction with respect to the (0001) plane.
6. The nitride semiconductor light-emitting device according to claim 1 , wherein
the barrier layer is formed of a nitride semiconductor containing In and Ga.
7. The nitride semiconductor light-emitting device according to claim 1 , wherein
the second semiconductor layer is formed in a position within 500 nm toward the nitride semiconductor substrate from a surface on a side closer to the nitride semiconductor substrate of the active layer.
8. The nitride semiconductor light-emitting device according to claim 1 , wherein
the well layer is formed of a nitride semiconductor of which In composition is 10% or higher.
9. The nitride semiconductor light-emitting device according to claim 1 , wherein
the well layer is formed of a nitride semiconductor containing Al.
10. The nitride semiconductor light-emitting device according to claim 1 , wherein
the nitride semiconductor light-emitting device is a laser device.