Light emitting device
Disclosed are a light emitting device. A light emitting diode comprises 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 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 undoped GaN layer on the second N-type semiconductor layer;
an active layer on the undoped GaN 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,
wherein the first and second N-type semiconductor layers have a Si impurity concentration different from each other, and
wherein at least one of the first and second N-type semiconductor layers comprises an N-type GaN layer.
2. The light emitting device according to claim 1 , wherein the second N-type semiconductor layer has a Si impurity concentration lower than a Si impurity concentration of the first N-type semiconductor layer.
3. The light emitting device according to claim 1 , wherein the undoped GaN layer is between the second N-type semiconductor layer and the active layer.
4. The light emitting device according to claim 1 , wherein the first and second N-type semiconductor layers comprise an N-type GaN layer.
5. The light emitting device according to claim 1 , wherein the second N-type semiconductor layer has a dislocation density lower than a dislocation density of the first N-type semiconductor layer.
6. The light emitting device according to claim 1 , further comprising a first electrode on a first portion of the second N-type semiconductor layer and a second electrode on the P-type semiconductor layer.
7. The light emitting device according to claim 6 , further comprising an ohmic electrode layer between the second electrode layer and the P-type semiconductor layer.
8. A light emitting device comprising:
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 a first portion of the second N-type semiconductor layer;
an undoped GaN layer between the second N-type semiconductor layer and the active layer;
a P-type semiconductor layer on the active layer;
a first electrode on a second portion of the second N-type semiconductor layers; and
a second electrode on the P-type semiconductor 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,
wherein the first and second N-type semiconductor layers have a Si impurity concentration different from each other, and
wherein the first and second N-type semiconductor layers comprise an N-type GaN layer.
9. The light emitting device according to claim 8 , wherein the second N-type semiconductor layer has a Si impurity concentration lower than a Si impurity concentration of the first N-type semiconductor layer.
10. The light emitting device according to claim 8 , wherein the second N-type semiconductor layer has a dislocation density lower than a dislocation density of the first N-type semiconductor layer.
11. The light emitting device according to claim 8 , further comprising an ohmic electrode layer between the second electrode layer and the P-type semiconductor layer.
12. A light emitting device comprising:
a substrate;
a first N-type semiconductor layer including a GaN layer on the substrate;
a second N-type semiconductor layer including a GaN layer on the first N-type semiconductor layer;
an undoped GaN layer on the second N-type semiconductor layer;
an active layer on the undoped GaN layer;
a P-type GaN layer on the active layer; and
a first electrode on a first portion of the second N-type semiconductor layer and a second electrode on the P-type GaN layer,
wherein the first and second N-type semiconductor layers have a Si impurity concentration different from each other, and
wherein the second N-type semiconductor layer has a Si impurity concentration lower than a Si impurity concentration of the first N-type semiconductor layer.
13. The light emitting device according to claim 12 , wherein the second N-type semiconductor layer has a dislocation density lower than a dislocation density of the first N-type semiconductor layer.
14. The light emitting device according to claim 12 , further comprising an ohmic electrode layer between the second electrode layer and the P-type GaN layer.