III-nitride semiconductor light emitting device
The present III-nitride semiconductor light-emitting device comprises: a first III-nitride semiconductor layer having a first conductivity type; a second III-nitride semiconductor layer having a second conductivity type different from the first conductivity type; an active layer disposed between the first III-nitride semiconductor layer and the second III-nitride semiconductor layer and generating light by recombination of electrons and holes; and a depletion barrier layer brought into contact with the active layer and having a first conductivity type.
1. A III-nitride semiconductor light-emitting device, comprising:
a first III-nitride semiconductor layer of a first conductivity type;
a second III-nitride semiconductor layer of a second conductivity type wherein the second conductivity type is different from the first conductivity type;
an active layer disposed between the first III-nitride semiconductor layer and the second III-nitride semiconductor layer, the active layer generating light by recombination of electrons and holes; and
a depletion barrier layer brought into contact with the active layer, the depletion barrier layer being of the first conductivity type, wherein the depletion barrier layer has a doping concentration of 1×10 19 cm −3 to 5×10 20 cm −3 , and wherein the distance between the depletion barrier layer and the second III-nitride semiconductor layer ranges from 50 nm to 300 nm.
2. The III-nitride semiconductor light-emitting device of claim 1 , wherein the depletion barrier layer has a thickness of 40 Å to 500 Å.
3. The III-nitride semiconductor light-emitting device of claim 1 , wherein the depletion barrier layer is made of GaN.
4. The III-nitride semiconductor light-emitting device of claim 1 , further comprising a third undoped III-nitride semiconductor layer disposed between the depletion barrier layer and the first III-nitride semiconductor layer.
5. The III-nitride semiconductor light-emitting device of claim 4 , wherein the third III-nitride semiconductor layer is made of GaN.
6. The III-nitride semiconductor light-emitting device of claim 1 , wherein the active layer comprises an In x Ga 1-x N layer on the contact side with the depletion barrier layer.
7. The III-nitride semiconductor light-emitting device of claim 6 , wherein x is equal to or smaller than 0.04.
8. The III-nitride semiconductor light-emitting device of claim 7 , wherein x is greater than 0.
9. The III-nitride semiconductor light-emitting device of claim 8 , wherein the In x Ga 1-x N layer is undoped.
10. The III-nitride semiconductor light-emitting device of claim 9 , wherein the In x Ga 1-x N layer has a thickness of 300 Å to 0.15 μm.
11. The III-nitride semiconductor light-emitting device of claim 10 , wherein the depletion barrier layer is made of GaN with a thickness of 40 Å to 500 Å.
12. The III-nitride semiconductor light-emitting device of claim 11 , comprising an undoped GaN layer disposed between the depletion barrier layer and the first III-nitride semiconductor layer.
13. The III-nitride semiconductor light-emitting device of claim 12 , wherein the undoped GaN layer has a thickness of 0.1 μm to 0.3 μm.