Light emitting device having undoped GaN layer
Disclosed is a light emitting device. A light emitting device comprises a plurality of N-type semiconductor layers including a first N-type semiconductor layer and a second N-type semiconductor layer on the first N-type semiconductor layer, an active layer on the second N-type semiconductor layer, and a P-type semiconductor layer on the active layer, wherein the first N-type semiconductor layer comprises a Si doped Nitride layer and the second N-type semiconductor layer comprises a Si doped Nitride layer, and wherein the first and second N-type semiconductor layers have a Si impurity concentration different from each other.
1. A light emitting device comprising:
a substrate;
a first undoped GaN layer on the substrate;
a first n-type semiconductor layer on the first undoped GaN layer;
a second undoped GaN layer on the first n-type semiconductor layer;
a second n-type semiconductor layer on the second undoped GaN layer;
an active layer on the second n-type semiconductor layer;
a p-type semiconductor layer on the active layer;
an ohmic electrode layer on the p-type semiconductor layer; and
a second electrode on the p-type semiconductor layer.
2. The light emitting device according to claim 1 , further comprising a third undoped GaN layer on the second n-type semiconductor layer.
3. The light emitting device according to claim 1 , wherein the first n-type semiconductor layer has a Si impurity concentration different from that of the second n-type semiconductor layer, and wherein the Si concentration of the first n-type semiconductor layer is greater than that of the second n-type semiconductor layer.
4. The light emitting device according to claim 1 , wherein the first n-type semiconductor layer is thicker than the first undoped GaN layer.
5. The light emitting device according to claim 1 , wherein the first n-type semiconductor layer is thicker than the second undoped GaN layer.
6. The light emitting device according to claim 1 , further comprising a first electrode on a first portion of the first n-type semiconductor layer.
7. The light emitting device according to claim 1 , wherein the ohmic electrode layer is directly disposed on the p-type semiconductor layer.
8. The light emitting device according to claim 2 , further comprising a third n-type semiconductor layer on the third undoped GaN layer.
9. The light emitting device according to claim 8 , wherein the first n-type semiconductor layer has a Si impurity concentration different from that of the second n-type semiconductor layer, and wherein the Si concentration of the first n-type semiconductor layer is greater than that of the third n-type semiconductor layer.
10. The light emitting device according to claim 8 , wherein a Si concentration of the second n-type semiconductor layer is greater than that of the third n-type semiconductor layer.
11. A light emitting device comprising:
a substrate;
a first undoped GaN layer on the substrate;
a first n-type semiconductor layer on the first undoped GaN layer;
a second undoped GaN layer on the first n-type semiconductor layer;
a second n-type semiconductor layer on the second undoped GaN layer;
an active layer on the second n-type semiconductor layer;
a p-type semiconductor layer on the active layer; and
a first electrode on the p-type semiconductor layer,
wherein the first n-type semiconductor layer is thicker than the first undoped GaN layer.
12. The light emitting device according to claim 11 , further comprising an ohmic electrode layer on the p-type semiconductor layer.
13. The light emitting device according to claim 11 , wherein the first n-type semiconductor layer is thicker than the second undoped GaN layer.
14. The light emitting device according to claim 11 , further comprising a second electrode on a first portion of the first n-type semiconductor layer.
15. The light emitting device according to claim 11 , further comprising a third undoped GaN layer on second n-type semiconductor layer.
16. The light emitting device according to claim 11 , wherein a Si concentration of the first n-type semiconductor layer is different from that of the second n-type semiconductor layer.
17. The light emitting device according to claim 12 , wherein the ohmic electrode layer is directly disposed on the p-type semiconductor layer.
18. The light emitting device according to claim 15 , further comprising a third n-type semiconductor layer on the third undoped GaN layer.
19. The light emitting device according to claim 18 , wherein a Si concentration of the first n-type semiconductor layer is greater than that of the third n-type semiconductor layer.
20. The light emitting device according to claim 16 , wherein the Si concentration of the first n-type semiconductor layer is greater than that of the second n-type semiconductor layer.