Light emitting device
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;
at least two n-type semiconductor layers on the substrate, each of the at least two n-type semiconductor layers having a different Si concentration;
a first n-type semiconductor layer on the at least two n-type semiconductor layers, the first n-type semiconductor layer having less Si concentration than 5×10 18 /cm 3 ;
an active layer directly on the first n-type semiconductor layer;
a p-type semiconductor layer on the active layer; and
an electrode on the p-type semiconductor layer.
2. The light emitting device according to claim 1 , wherein the first n-type semiconductor layer has a Si concentration lower than a Si concentration of the at least two n-type semiconductor layers.
3. The light emitting device according to claim 1 , wherein the at least two n-type semiconductor layers comprises an n-type GaN layer.
4. The light emitting device according to claim 1 , further comprising an undoped GaN layer between the first n-type semiconductor layer and a top layer of the at least two n-type semiconductor layers.
5. The light emitting device according to claim 1 , wherein the first n-type semiconductor layer has a dislocation density lower than a dislocation density of the at least two n-type semiconductor layers.
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, and
a second electrode on the p-type semiconductor layer.
7. The light emitting device according to claim 1 , wherein the first n-type semiconductor layer comprises a GaN layer.
8. The light emitting device according to claim 1 , wherein the at least two n-type semiconductor layers comprise a first GaN layer and a second GaN layer disposed on the first GaN layer.
9. The light emitting device according to claim 1 , wherein the active layer comprises InGaN/GaN layer.
10. The light emitting device according to claim 1 , wherein the p-type semiconductor layer comprises a GaN layer.
11. The light emitting device according to claim 6 , further comprising an ohmic electrode layer between the second electrode and the p-type semiconductor layer.
12. A light emitting device comprising:
at least two n-type semiconductor layers, each of the at least two n-type semiconductor layers having a different Si concentration;
an undoped GaN layer on a top surface of the at least two n-type semiconductor layers;
a first n-type semiconductor layer on the at least two n-type semiconductor layers, the first n-type semiconductor layer having less Si concentration than 5×10 18 /cm 3 ;
an active layer directly on a first portion of the first n-type semiconductor layer;
a p-type semiconductor layer on the active layer;
a first electrode on a second portion of the first n-type semiconductor layer;
a second electrode on the p-type semiconductor layer.
13. The light emitting device according to claim 12 , wherein the first n-type semiconductor layer has a Si concentration lower than a Si concentration of the at least two n-type semiconductor layers.
14. The light emitting device according to claim 12 , wherein the at least two n-type semiconductor layers comprises an n-type GaN layer.
15. The light emitting device according to claim 12 , wherein the first n-type semiconductor layer has a dislocation density lower than a dislocation density of the at least two n-type semiconductor layers.
16. The light emitting device according to claim 12 , further comprising an ohmic electrode layer between the second electrode and the p-type semiconductor layer.
17. The light emitting device according to claim 12 , wherein the first n-type semiconductor layer comprises a GaN layer.
18. The light emtting device according to claim 12 , wherein the at least two n-type semiconductor layers comprise a first GaN layer and a second GaN layer disposed on the first GaN layer.
19. The light emitting device according to claim 12 , wherein the active layer comprises InGaN/GaN layer.
20. The light emitting device according to claim 12 , wherein the p-type semiconductor layer comprises a GaN layer.