Nitride semiconductor light emitting device and fabrication method thereof

1. A light emitting device, comprising:

a first semiconductor layer;

an In x Ga 1−x N layer on the first semiconductor layer;

an active layer of a single or multiple quantum well structure on the In x Ga 1−x N layer and including an In y Ga 1−y N well layer and a multilayer barrier layer; and

a second semiconductor layer on the active layer,

wherein the In x Ga 1−x N layer comprises indium lower in content than the indium included in the In y Ga 1−y N well layer in which y satisfies a relation of 0<y<0.35, and

wherein the multilayer barrier layer of the active layer is formed of one of a multilayer barrier layer including an InGaN layer, an AlInN layer and an InGaN/GaN superlattice structure layer; a multilayer barrier layer including an InGaN layer, an AlInN layer and an InGaN layer; a multilayer barrier layer including an InGaN layer, an AlInN layer and a GaN layer; or a multilayer barrier layer including an InGaN layer and AlInN layer.

2. The light emitting device of claim 1 , wherein the first semiconductor layer comprises:

an undoped or In-doped GaN based layer; and

a first electrode layer formed on the GaN based layer.

3. The light emitting device of claim 2 , further comprising:

a second electrode layer formed on the second semiconductor layer.

4. The light emitting device of claim 2 , wherein the first electrode layer is a GaN based layer co-doped with silicon and indium.

5. The light emitting device of claim 3 , wherein the second electrode layer is formed in a superlattice structure including In.

6. The light emitting device of claim 3 , wherein the second electrode layer is doped with silicon.

7. The light emitting device of claim 3 , wherein the first electrode layer included in the first semiconductor layer and the second electrode layer are n-type semiconductors.

8. The light emitting device of claim 3 , further comprising:

a transparent electrode provided on the second electrode layer.

9. The light emitting device of claim 8 , wherein the transparent electrode is formed of a transparent conductive oxide or transparent resistive material.

10. The light emitting device of claim 8 , wherein a material of the transparent electrode is selected from the group including ITO, ZnO, RuO x , IrO x , NiO, or Au alloy metal including Ni.

11. The light emitting device of claim 1 , further comprising:

a substrate under the first semiconductor layer; and

a buffer layer formed on the substrate.

12. The light emitting device of claim 11 , wherein the buffer layer is formed in a structure selected from the group including an AlInN/GaN lamination structure, an InGaN/GaN superlattice structure, an In x Ga 1−x N/GaN lamination structure and an Al x In y Ga 1−(x+y) N/In x Ga 1−x N/GaN lamination structure.

13. The light emitting device of claim 1 , wherein the second semiconductor layer is formed by doping with p-type impurities.

14. The light emitting device of claim 1 , wherein x in the In x Ga 1−x N layer satisfies a relation of 0<x<0.1.

15. A light emitting device, comprising:

a first n-type semiconductor layer;

an In x Ga 1−x N layer on the first n-type semiconductor layer;

an active layer of a single or multiple quantum well structure on the In x Ga 1−x N layer and including an In y Ga 1−y N well layer and a multilayer barrier layer;

a p-type semiconductor layer on the active layer;

a second n-type semiconductor layer on the p-type semiconductor layer, wherein the In x Ga 1−x N layer comprises indium lower in content than the indium included in the In y Ga 1−y N well layer in which y satisfies a relation of 0<y<0.35; and

a transparent electrode on the second n-type semiconductor layer,

wherein a material of the transparent electrode is selected from the group including ITO, ZnO, RuO x , IrO x , NiO, or Au alloy metal including Ni.

16. The light emitting device of claim 15 , further comprising:

a substrate; and

a buffer layer formed on the substrate,

wherein the buffer layer is formed in a structure selected from the group including an AlInN/GaN lamination structure, an InGaN/GaN superlattice structure, an In x Ga 1−x N/GaN lamination structure and an Al x In y Ga 1−(x+y) N/In x Ga 1−x N/GaN lamination structure.

17. The light emitting device of claim 15 , wherein the second n-type semiconductor layer is formed in an InGaN/InGaN superlattice structure or in an InGaN/AlInGaN superlattice structure.

18. The light emitting device of claim 15 , wherein the multilayer barrier layer of the active layer is formed of one of a multilayer barrier layer including an InGaN layer, an AlInN layer and an InGaN/GaN superlattice structure layer; a multilayer barrier layer including an InGaN layer, an AlInN layer and an InGaN layer; a multilayer barrier layer including an InGaN layer, an AlInN layer and a GaN layer; or a multilayer barrier layer including an InGaN layer and AlInN layer.

19. A light emitting device, comprising:

a first n-type semiconductor layer;

an In x Ga 1−x N layer on the first n-type semiconductor layer;

an active layer of a single or multiple quantum well structure on the In x Ga 1−x N layer and including an In y Ga 1−y N well layer and a multilayer barrier layer;

a p-type semiconductor layer on the active layer; and

a second n-type semiconductor layer on the p-type semiconductor layer,

wherein the In x Ga 1−x N layer comprises indium lower in content than the indium included in the In y Ga 1−y N well layer in which y satisfies a relation of 0<y<0.35, and

wherein x in the In x Ga 1−x N layer satisfies a relation of 0<x<0.1.

20. The light emitting device of claim 19 , further comprising:

a transparent electrode on the second n-type semiconductor layer,

wherein a material of the transparent electrode is selected from the group including ITO, ZnO, RuO x , IrO x , NiO, or Au alloy metal including Ni.