Type II broadband or polychromatic LED's

• US 20060124938A1
• Filed: 12/09/2004
• Published: 06/15/2006
• Est. Priority Date: 12/09/2004
• Status: Active Grant

• Current Assignee: 3M Innovative Properties Company (3M Company)
• Original Assignee: 3M Innovative Properties Company (3M Company)
• Inventors: Haase, Michael A., Miller, Thomas J.
• Granted Patent: US 7,719,015 B2
• Time in Patent Office: Days
• US Class Current: 257/79
• CPC Class Codes: H01L 33/06 within the light emitting region, e.g. quantum confinement structure or tunnel barrier
• CPC Class Codes: H01L 33/08 with a plurality of light emitting regions, e.g. laterally discontinuous light emitting layer or photoluminescent region integrated within the semiconductor body H01L27/15 takes precedence
• CPC Class Codes: H01L 33/28 containing only elements of Group II and Group VI of the Periodic Table

Abstract

An LED is provided comprising two or more light-emitting Type II interfaces wherein at least two of the Type II interfaces differ in transition energy by at least 5%, or more typically by at least 10%, and wherein at least one of the Type II interfaces is within a pn junction. Alternately, an LED is provided comprising two or more light-emitting Type II interfaces wherein at least two of the Type II interfaces differ in transition energy by at least 5%, or more typically by at least 10%. The Type II interfaces may include interfaces from a layer which is an electron quantum well and not a hole quantum well, interfaces to a layer which is a hole quantum well and not an electron quantum well; and interfaces that satisfy both conditions simultaneously. The Type II interfaces may be within a pn or pin junction or not within a pn or pin junction. In the later case, emission from the Type II interfaces may be photopumped by a nearby light source. The LED may be a white or near-white light LED. In addition, graphic display devices and illumination devices comprising the semiconductor device according to the present invention are provided.

Claims

1. An LED comprising two or more Type II interfaces wherein at least two of said two or more Type II interfaces differ in transition energy by at least 5% and wherein at least one of said two or more Type II interfaces is within a pn junction.

2. The LED according to claim 1 wherein at least two of said two or more Type II interfaces differ in transition energy by at least 10%.

3. The LED according to claim 1 wherein at least one of said two or more Type II interfaces is from a layer which is an electron quantum well and not a hole quantum well.

4. The LED according to claim 1 wherein at least one of said two or more Type II interfaces is to a layer which is a hole quantum well and not an electron quantum well.

5. The LED according to claim 1 wherein at least one of said two or more Type II interfaces is from a layer which is an electron quantum well and not a hole quantum well to a layer which is a hole quantum well and not an electron quantum well.

6. The LED according to claim 2 wherein at least one of said two or more Type II interfaces is from a layer which is an electron quantum well and not a hole quantum well.

7. The LED according to claim 2 wherein at least one of said two or more Type II interfaces is to a layer which is a hole quantum well and not an electron quantum well.

8. The LED according to claim 2 wherein at least one of said two or more Type II interfaces is from a layer which is an electron quantum well and not a hole quantum well to a layer which is a hole quantum well and not an electron quantum well.

9. The LED according to claim 1 wherein a first Type II interface of said two or more Type II interfaces has a first transition energy corresponding to yellow, green, blue or violet wavelength visible light, and wherein a second Type II interface of said two or more Type II interfaces has a second transition energy corresponding to red, orange or yellow wavelength visible light.

10. The LED according to claim 5 wherein a first Type II interface of said two or more Type II interfaces has a first transition energy corresponding to yellow, green, blue or violet wavelength visible light, and wherein a second Type II interface of said two or more Type II interfaces has a second transition energy corresponding to red, orange or yellow wavelength visible light.

11. The LED according to claim 8 wherein a first Type II interface of said two or more Type II interfaces has a first transition energy corresponding to yellow, green, blue or violet wavelength visible light, and wherein a second Type II interface of said two or more Type II interfaces has a second transition energy corresponding to red, orange or yellow wavelength visible light.

12. A graphic display device comprising the LED according to claim 1.

13. An illumination device comprising the LED according to claim 1.

14. A graphic display device comprising the LED according to claim 5.

15. An illumination device comprising the LED according to claim 5.

16. A graphic display device comprising the LED according to claim 8.

17. An illumination device comprising the LED according to claim 8.

18. An LED comprising two or more light-emitting Type II interfaces wherein at least two of said two or more Type II interfaces differ in transition energy by at least 5%.

19. The LED according to claim 18 wherein at least two of said two or more Type II interfaces differ in transition energy by at least 10%.

20. The LED according to claim 18 wherein at least one of said two or more Type II interfaces is from a layer which is an electron quantum well and not a hole quantum well.

21. The LED according to claim 18 wherein at least one of said two or more Type II interfaces is to a layer which is a hole quantum well and not an electron quantum well.

22. The LED according to claim 18 wherein at least one of said two or more Type II interfaces is from a layer which is an electron quantum well and not a hole quantum well to a layer which is a hole quantum well and not an electron quantum well.

23. The LED according to claim 19 wherein at least one of said two or more Type II interfaces is from a layer which is an electron quantum well and not a hole quantum well.

24. The LED according to claim 19 wherein at least one of said two or more Type II interfaces is to a layer which is a hole quantum well and not an electron quantum well.

25. The LED according to claim 19 wherein at least one of said two or more Type II interfaces is from a layer which is an electron quantum well and not a hole quantum well to a layer which is a hole quantum well and not an electron quantum well.

26. The LED according to claim 18 additionally comprising an LED capable of emitting green, blue or violet wavelength visible light, wherein a first Type II interface of said two or more Type II interfaces has a first transition energy corresponding to orange, yellow or green wavelength visible light, and wherein a second Type II interface of said two or more Type II interfaces has a second transition energy corresponding to red, orange or yellow wavelength visible light.

27. The LED according to claim 22 additionally comprising an LED capable of emitting green, blue or violet wavelength visible light, wherein a first Type II interface of said two or more Type II interfaces has a first transition energy corresponding to orange, yellow or green wavelength visible light, and wherein a second Type II interface of said two or more Type II interfaces has a second transition energy corresponding to red, orange or yellow wavelength visible light.

28. The LED according to claim 25 additionally comprising an LED capable of emitting green, blue or violet wavelength visible light, wherein a first Type II interface of said two or more Type II interfaces has a first transition energy corresponding to orange, yellow or green wavelength visible light, and wherein a second Type II interface of said two or more Type II interfaces has a second transition energy corresponding to red, orange or yellow wavelength visible light.

29. A graphic display device comprising the LED according to claim 18.

30. An illumination device comprising the LED according to claim 18.

31. A graphic display device comprising the LED according to claim 22.

32. An illumination device comprising the LED according to claim 22.

33. A graphic display device comprising the LED according to claim 25.

34. An illumination device comprising the LED according to claim 25.

35. A liquid crystal display comprising the LED according to claim 18.

36. A liquid crystal display comprising the LED according to claim 26, wherein said LED and said first and second transition energies are matched to the color filters of the liquid crystal display.