Nitride semiconductor light-emitting device

1. A nitride semiconductor light-emitting device, comprising:

a first conductive nitride semiconductor layer;

an active layer formed on the first conductive nitride semiconductor layer, and having at least one quantum well layer and at least one quantum barrier layer alternatively laminated; and

a second conductive nitride semiconductor layer formed on the active layer,

wherein

at least one of the quantum well layer and quantum barrier layer in the active layer is doped with elemental Al in a concentration that ranges from 0.2 to 0.6%.

2. The nitride semiconductor light-emitting device as set forth in claim 1 , wherein the active layer has a multiple quantum well structure composed of a plurality of quantum barrier layers and a plurality of quantum well layers.

3. The nitride semiconductor light-emitting device as set forth in claim 2 , wherein all the quantum barrier layers in the active layer are doped with elemental Al in a concentration that ranges from 0.2 to 0.6%.

4. The nitride semiconductor light-emitting device as set forth in claim 2 , wherein all the quantum well layers in the active layer are doped with elemental Al in a concentration that ranges from 0.2 to 0.6%.

5. The nitride semiconductor light-emitting device as set forth in claim 1 , wherein

the quantum barrier layer is composed of material having the formula of In x1 Ga 1−x1 N, where x 1 is a number between 0 and 1; and

the quantum well layer is composed of material having the formula of In x2 Ga 1−x2 N, where x 2 is a number between 0 and 1, and having an energy band gap smaller than that of the quantum barrier layer.

6. A nitride semiconductor light-emitting device, comprising:

a first conductive nitride semiconductor layer;

an active layer formed on the first conductive nitride semiconductor layer, and having at least one quantum well layer and at least one quantum barrier layer alternatively laminated; and

a second conductive nitride semiconductor layer formed on the active layer,

wherein

at least one of the quantum well layer and quantum barrier layer in the active layer is doped with elemental Al in a concentration of less than 1%;

the quantum barrier layer is composed of material having the formula of In x1 Ga 1−x1 N, where x 1 is a number between 0 and 1; and

the quantum well layer is composed of material having the formula of In x2 Ga 1−x2 N, where x 2 is a number between 0 and 1, and having an energy band gap smaller than that of the quantum barrier layer.

7. A nitride semiconductor light-emitting device, comprising:

a first conductive nitride semiconductor layer;

an active layer formed on the first conductive nitride semiconductor layer; and

a second conductive nitride semiconductor layer formed on the active layer,

wherein

said active layer comprises at least one quantum well layer and at least one quantum barrier layer laminated with said at least one quantum well layer; and

at least one of the quantum well layer and quantum barrier layer in the active layer is doped with Al and contains Al dopants in a concentration of higher than 0% and less than 1%.

8. The nitride semiconductor light-emitting device as set forth in claim 7 , wherein said concentration ranges from 0.2 to 0.6%.

9. The nitride semiconductor light-emitting device as set forth in claim 7 , wherein

the quantum barrier layer is made of In x1 Ga 1−x1 N, where x 1 is a number between 0 and 1; and

the quantum well layer is made of In x2 Ga 1−x2 N, where x 2 is a number between 0 and 1, and has an energy band gap smaller than that of the quantum barrier layer.

10. The nitride semiconductor light-emitting device as set forth in claim 7 , wherein the active layer has a multiple quantum well structure comprising a plurality of quantum barrier layers and a plurality of quantum well layers, and wherein said quantum baffler layers and said quantum well layers are alternatingly laminated to define said active layer.

11. The nitride semiconductor light-emitting device as set forth in claim 10 , wherein all the quantum barrier layers in the active layer are doped with Al, and each of said quantum barrier layers contains Al dopants in a concentration of higher than 0% and less than 1%.

12. The nitride semiconductor light-emitting device as set forth in claim 10 , wherein all the quantum well layers in the active layer are doped with Al, and each of said quantum well layers contains Al dopants in a concentration of higher than 0% and less than 1%.

13. The nitride semiconductor light-emitting device as set forth in claim 8 , wherein

the quantum barrier layer is made of In x1 Ga 1−x1 N, where x 1 is a number between 0 and 1; and

the quantum well layer is made of In x2 Ga 1−x2 N, where x 2 is a number between 0 and 1, and has an energy band gap smaller than that of the quantum barrier layer.

14. The nitride semiconductor light-emitting device as set forth in claim 8 , wherein the active layer has a multiple quantum well structure comprising a plurality of quantum barrier layers and a plurality of quantum well layers, and wherein said quantum barrier layers and said quantum well layers are alternatingly laminated to define said active layer.

15. The nitride semiconductor light-emitting device as set forth in claim 14 , wherein all the quantum barrier layers in the active layer are doped with Al, and each of said quantum barrier layers contains Al dopants in a concentration that ranges from 0.2 to 0.6%.

16. The nitride semiconductor light-emitting device as set forth in claim 14 , wherein all the quantum well layers in the active layer are doped with Al, and each of said quantum well layers contains Al dopants in a concentration that ranges from 0.2 to 0.6%.