Group III nitride based light emitting diode structures with multiple quantum well structures having varying well thicknesses

1. A Group III nitride based light emitting diode, comprising:

a p-type Group III nitride based semiconductor layer;

an n-type Group III nitride based semiconductor layer; and

a Group III nitride based active region between the p-type Group III nitride based semiconductor layer and the n-type Group III nitride based semiconductor layer, the active region comprising a plurality of sequentially stacked Group III nitride based well layers;

wherein the plurality of well layers comprises a first well layer having a first thickness and a second well layer having a second thickness, the second well layer is between the p-type Group III nitride based semiconductor layer and the first well layer, and the second thickness is greater than the first thickness;

wherein, in response to being energized, the light emitting diode emits light having a full width half maximum (FWHM) that is less than about 30 nm.

2. The light emitting diode of claim 1 , wherein the light emitted by the light emitting diode has a FWHM that is less than about 20 nm.

3. The light emitting diode of claim 1 , wherein the first well layer has a first bandgap, the second well layer has a second bandgap, and the first bandgap is less than the second bandgap.

4. The light emitting diode of claim 1 , wherein the first well layer comprises In X1 Ga 1-X1 N, the second well layer comprises In X2 Ga 1-X2 N, and X 1 >X 2 .

5. The light emitting diode of claim 1 , wherein the plurality of well layers have respective thicknesses that decrease with distance from the p-type Group III nitride based semiconductor layer.

6. The light emitting diode of claim 5 , wherein the plurality of well layers have respective bandgaps that decrease with distance from the p-type Group III nitride based semiconductor layer.

7. The light emitting diode of claim 5 , wherein the plurality of well layers comprise In X Ga 1-X N, where X varies in inverse proportion to the thickness of the respective well layers.

8. The light emitting diode of claim 5 , wherein the plurality of well layers have respective band gaps that vary in proportion to the thickness of the respective well layers.

9. The light emitting diode of claim 5 , wherein the plurality of well layers comprise In X Ga 1-X N where 0<X<1, and wherein the plurality of well layers have indium compositions that increase with distance from the p-type Group III nitride based semiconductor layer.

10. The light emitting diode of claim 5 , wherein the plurality of well layers have thicknesses that decrease approximately linearly from well layer to well layer.

11. The light emitting diode of claim 1 , wherein the plurality of well layers comprises a first plurality of well layers having the first thickness and a second plurality of well layers having the second thickness.

12. The light emitting diode of claim 1 , wherein the plurality of well layers comprises a first plurality of well layers having the first thickness and a second plurality of well layers having thicknesses that increase from the first thickness to the second thickness.

13. The light emitting diode of claim 12 , wherein the second plurality of well layers have thicknesses that increase approximately linearly from the first thickness to the second thickness.

14. The light emitting diode of claim 11 , wherein the second plurality of well layers is between the first plurality of well layers and the P-N junction.

15. The light emitting diode of claim 1 , wherein the plurality of well layers comprises a first plurality of well layers having thicknesses that increase from the first thickness to the second thickness and a second plurality of well layers having the second thickness.

16. The light emitting diode of claim 15 , wherein the first plurality of well layers have thicknesses that increase approximately linearly from the first thickness to the second thickness.

17. The light emitting diode of claim 15 , wherein the second plurality of well layers is between the first plurality of well layers and the p-type Group III nitride based semiconductor layer.

18. The light emitting diode of claim 1 , wherein the second thickness is at least about 18% greater than the first thickness.

19. The light emitting diode of claim 1 , wherein the second thickness is about 25% greater than the first thickness.

20. The light emitting diode of claim 1 , wherein the well layers comprise indium, and wherein a composition of indium in the first well layer is greater than a composition of indium in the second well layer.

21. The light emitting diode of claim 20 , wherein the composition of indium in the well layers ranges from about 0.05 to about 0.5.

22. The light emitting diode of claim 1 , further comprising a plurality of barrier layers on respective ones of the well layers including a first barrier layer on the first well layer between the first well layer and the p-type Group III nitride based semiconductor layer and a second barrier layer on the second well layer between the second well layer and the p-type Group III nitride based semiconductor layer, wherein the first barrier layer is thicker than the second barrier layer.

23. The light emitting diode of claim 1 , further comprising a plurality of barrier layers on respective ones of the plurality of well layers, the plurality of barrier layers having thicknesses that increase with distance from the p-type Group III nitride based semiconductor layer.

24. The light emitting diode of claim 1 , further comprising a plurality of barrier layers on respective ones of the well layers including a first barrier layer on the first well layer between the first well layer and the p-type Group III nitride based semiconductor layer and a second barrier layer on the second well layer between the second well layer and the p-type Group III nitride based semiconductor layer, wherein the second barrier layer is thicker than the first barrier layer.

25. The light emitting diode of claim 1 , further comprising a plurality of barrier layers on respective ones of the plurality of well layers, the plurality of barrier layers having thicknesses that decrease with distance from the p-type Group III nitride based semiconductor layer.

26. The light emitting diode of claim 1 , wherein the active region comprises a plurality of well groups, each of the well groups comprises:

a Group III nitride based well support layer, wherein the Group III nitride based well layer is on the well support layer; and

a Group III nitride based well cap layer on the Group III nitride based well layer.

27. The light emitting diode of claim 26 , wherein a combined thickness of the well support layer and the well cap layer is from about 50 Å to about 400 Å.

28. The light emitting diode of claim 1 , wherein the well layers have thicknesses of from about 10 Å to about 50 Å.

29. A Group III nitride based light emitting diode, comprising:

an n-type Group III nitride based semiconductor layer;

a p-type Group III nitride based semiconductor layer forming a P-N junction with the n-type Group III nitride based semiconductor layer; and

a Group III nitride based active region comprising a plurality of sequentially stacked Group III nitride based wells including respective well layers adjacent the P-N junction;

wherein the plurality of well layers comprises a first well layer having a first thickness and a second well layer having a second thickness, the second well layer is between the P-N junction and the first well layer, and the second thickness is greater than the first thickness;

wherein, in response to being energized, the light emitting diode emits light having a full width half maximum (FWHM) that is less than about 30 nm.

30. A Group III nitride based light emitting diode, comprising:

a p-type Group III nitride based semiconductor layer;

an n-type Group III nitride based semiconductor layer that forms a P-N junction with the p-type Group III nitride based semiconductor layer; and

a Group III nitride based active region on the n-type Group III nitride based semiconductor layer, the active region comprising a plurality of sequentially stacked Group III nitride based wells including respective well layers;

wherein the plurality of well layers comprises a first well layer having a first thickness and a second well layer having a second thickness that is greater than the first thickness; and

wherein, in response to being energized, the light emitting diode emits light having a full width half maximum (FWHM) that is less than about 30 nm.

31. A Group III nitride based light emitting diode, comprising:

a first light emitting well layer having a first thickness and configured to generate light having a first dominant wavelength when energized by passing electric current therethrough; and

a second light emitting well layer having a second thickness that is different from the first thickness and that is configured to generate light having a second dominant wavelength when energized by passing electric current therethrough;

wherein the first dominant wavelength is no more than about 10 nm different from the second dominant wavelength.

32. The Group III nitride based light emitting diode of claim 31 , wherein the first dominant wavelength is no more than about 5 nm different from the second dominant wavelength.

33. The Group III nitride based light emitting diode of claim 31 , wherein the first dominant wavelength is no more than about 2.5 nm different from the second dominant wavelength.