Light emitting device and light emitting device package having the same
A light emitting device includes a nano-structure, a first semiconductor layer on the nano-structure, an active layer on the first semiconductor layer, and a second conductive semiconductor layer on the active layer. The nano-structure includes a graphene layer provided under the first semiconductor layer to make contact with the first semiconductor layer; and a plurality of nano-textures extending from a top surface of the graphene layer to the first semiconductor layer and in contact with the first semiconductor layer.
1. A light emitting device comprising:
a nano-structure;
a first semiconductor layer provided over the nano-structure;
an active layer provided over the first semiconductor layer;
a second conductive semiconductor layer provided over the active layer; and
a substrate disposed under the nano-structure,
wherein the nano-structure comprises:
a graphene layer provided under the first semiconductor layer and in contact with the first semiconductor layer; and
a plurality of nano-textures extending from a top surface of the graphene layer in a direction toward the first semiconductor layer and in contact with the first semiconductor layer, and
wherein the graphene layer comprises a plurality of openings, and a portion of the first semiconductor layer makes contact with a top surface of the substrate through each opening of the graphene layer.
2. The light emitting device of claim 1 , wherein the first semiconductor layer comprises an N type semiconductor layer, and the nano-structure is connected to the N type semiconductor layer.
3. The light emitting device of claim 1 , wherein the first semiconductor layer comprises a buffer layer on the nano-structures and an N type semiconductor layer on the buffer layer, and the nano-textures are contacted with the buffer layer and the N type semiconductor layer.
4. The light emitting device of claim 1 , wherein a lower portion of the first semiconductor layer is contacted with the top surface of the graphene layer through a region between the nano-textures.
5. The light emitting device of claim 1 , wherein the nano-textures comprise zinc oxide (ZnO).
6. The light emitting device of claim 1 , wherein the graphene layer is contacted with a top surface of the substrate.
7. The light emitting device of claim 1 , wherein each of the nano-textures has a lattice constant between a lattice constant of the substrate and a lattice constant of the first semiconductor layer.
8. The light emitting device of claim 1 , further comprising at least one of a transparent conductive layer and a reflective layer on the second conductive semiconductor layer.
9. The light emitting device of claim 1 , wherein the first semiconductor layer comprises a first conductive semiconductor layer, and is electrically connected to the nano-structure, and the graphene layer comprises a transparent electrode.
10. The light emitting device of claim 1 , wherein each nano-texture has a width in a range of 5 nm to 500 nm, and has a height in a range of 10 nm to 3 μm.
11. The light emitting device of claim 1 , wherein each nano-texture has a width in a range of 5 nm to 500 nm.
12. The light emitting device of claim 1 , wherein each nano-texture has a height in a range of 10 nm to 3 μm.
13. A light emitting device comprising:
a nano-structure;
a first semiconductor layer provide over the nano-structure;
an active layer provide over the first semiconductor layer;
a second conductive semiconductor layer provide over the active layer; and
a substrate disposed under the nano-structure,
wherein the nano-structure comprises:
a graphene layer provide under the first semiconductor layer and in contact with the first semiconductor layer;
a plurality of nano-textures extending from a top surface of the graphene layer in a direction toward the first semiconductor layer and in contact with the first semiconductor layer, and
wherein the graphene layer comprises a plurality of graphene patterns spaced apart from each other, and the nano-textures are disposed on the graphene patterns, respectively.
14. The light emitting device of claim 13 , wherein the first semiconductor layer is disposed between the graphene patterns and the substrate, and disposed in a region between the graphene patterns contacted with the graphene patterns disposed under a region between the substrate and the nano-textures.
15. The light emitting device of claim 13 , further comprising a first conductive semiconductor layer between the first semiconductor layer and the active layer,
wherein the first semiconductor layer comprises a buffer layer, and the buffer layer makes contact with the top surface of the substrate, a top surface of the graphene patterns, and the nano-textures.
16. The light emitting device of claim 13 , wherein an interval between the graphene patterns is in a range of 0.1 μm to 100 μm.
17. A light emitting device comprising:
a substrate;
a nano-structure on the substrate;
a first semiconductor layer disposed on the nano-structure;
a first electrode on a first region of the first semiconductor layer;
an active layer disposed on a top surface of the first semiconductor layer;
a second conductive semiconductor layer disposed on the active layer; and
a second electrode on the second conductive semiconductor layer,
wherein the nano-structure comprises:
a graphene layer disposed under the first semiconductor layer and contacted with the first semiconductor layer; and
a plurality of nano-textures extending from a top surface of the graphene layer in a direction toward the first semiconductor layer and contacted with the first semiconductor layer,
wherein a portion of the nano-structure overlaps with the first electrode in a vertical direction, and
wherein the graphene layer comprises a plurality of openings, and a portion of the first semiconductor layer makes contact with a top surface of the substrate through each opening of the graphene layer.
18. The light emitting device of claim 17 , wherein the first semiconductor layer comprises an N type semiconductor layer, and the nano-structure is connected to the N type semiconductor layer, and
wherein a lower portion of the first semiconductor layer is contacted with the top surface of the graphene layer through a region between the nano-textures.
19. The light emitting device of claim 17 , wherein the first semiconductor layer comprises a buffer layer on the nano-structures and an N type semiconductor layer on the buffer layer, and the nano-textures are contacted with the buffer layer and the N type semiconductor layer.
20. The light emitting device of claim 17 , wherein each nano-texture has a width in a range of 5 nm to 500 nm, and has a height in a range of 10 nm to 3 μm.