Adapting short-wavelength LED's for polychromatic, broadband, or “white” emission

• US 7,700,938 B2
• Filed: 07/14/2008
• Issued: 04/20/2010
• Est. Priority Date: 12/09/2004
• Status: Expired due to Fees

• Current Assignee: 3M Innovative Properties Company (3M Company)
• Original Assignee: 3M Innovative Properties Company (3M Company)
• Inventors: Smith, Terry L., Haase, Michael A., Miller, Thomas J., Sun, Xiaoguang
• Primary Examiner(s): PRENTY, MARK V
• Application Number:
  US12/172,549
• Publication Number:
  US 20080272362A1
• Time in Patent Office: 645 Days
• Field of Search: 257/13, 257/14, 257 88- 90, 257/98, 257/103
• US Class Current: 257/13
• CPC Class Codes: H01L 2224/05001 Internal layers
• CPC Class Codes: H01L 2224/05005 Structure
• CPC Class Codes: H01L 2224/05023 the whole internal layer protruding from the surface
• CPC Class Codes: H01L 2224/0508 being stacked
• CPC Class Codes: H01L 2224/05541 Structure
• CPC Class Codes: H01L 2224/05568 the whole external layer protruding from the surface
• CPC Class Codes: H01L 2224/14 of a plurality of bump connectors
• CPC Class Codes: H01L 24/05 of an individual bonding area
• CPC Class Codes: H01L 2924/00 Indexing scheme for arrangements or methods for connecting or disconnecting semiconductor or solid-state bodies as covered by H01L24/00
• CPC Class Codes: H01L 2924/13055 Insulated gate bipolar transistor [IGBT]
• CPC Class Codes: H01L 2924/13091 Metal-Oxide-Semiconductor Field-Effect Transistor [MOSFET]
• 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

Abstract

An adapted LED is provided comprising a short-wavelength LED and a re-emitting semiconductor construction, wherein the re-emitting semiconductor construction comprises at least one potential well not located within a pn junction. The potential well(s) are typically quantum well(s). The adapted LED may be a white or near-white light LED. The re-emitting semiconductor construction may additionally comprise absorbing layers surrounding or closely or immediately adjacent to the potential well(s). In addition, graphic display devices and illumination devices comprising the adapted LED according to the present invention are provided.

Claims

1. An adapted LED comprising an LED and a re-emitting semiconductor construction, wherein the re-emitting semiconductor construction comprises a first potential well having a first transition energy and an absorbing layer closely adjacent to the first potential well, the absorbing layer having a band gap energy greater than the first transition energy and smaller than an energy of a photon emitted by the LED, wherein the first transition energy corresponds to a yellow or green light, and wherein the re-emitting semiconductor construction further comprises a second potential well having a second transition energy corresponding to an orange or red light.

2. An adapted LED according to claim 1, wherein the LED is a UV, violet, blue or green LED.

3. An adapted LED according to claim 1, wherein the LED comprises a III-V semiconductor.

4. An adapted LED according to claim 1, wherein the LED comprises a GaN semiconductor.

5. An adapted LED according to claim 1, wherein the re-emitting semiconductor construction is not within a pn junction.

6. An adapted LED according to claim 1, wherein the re-emitting semiconductor construction comprises a quantum well.

7. An adapted LED according to claim 1, wherein the re-emitting semiconductor construction comprises a II-VI semiconductor.

8. An adapted LED according to claim 1, wherein the re-emitting semiconductor construction comprises a Cd(Mg)ZnSe alloy.

9. An adapted LED according to claim 1, wherein the re-emitting semiconductor construction comprises ZnSe, CdSe, MgSe, ZnS, or MgS, or an alloy thereof.

10. An adapted LED according to claim 1, wherein the re-emitting semiconductor construction comprises ZnSe, BeSe, or MgSe, or an alloy thereof.

11. An adapted LED according to claim 1, wherein the first potential well comprises a quantum well.

12. An adapted LED according to claim 1, wherein a thickness of the first potential well is 100 nm or less.

13. An adapted LED according to claim 1, wherein a thickness of the first potential well is between 2 nm and 35 nm.

14. An adapted LED according to claim 1, wherein a thickness of the first potential well is about 10 nm.

15. An adapted LED according to claim 1, wherein a thickness of the absorbing layer is about 1000 nm.

16. An adapted LED according to claim 1, wherein the re-emitting semiconductor construction is capable of re-emitting one or more of a blue, green, yellow, orange, red, and white light.

17. An adapted LED according to claim 1, wherein the absorbing layer is immediately adjacent to the first potential well.

18. An adapted LED according to claim 1, wherein the absorbing layer is adapted to generate electron-hole pairs by absorbing photons emitted by the LED, and to direct the generated electron-hole pairs toward the first potential well.

19. An adapted LED according to claim 1, wherein the absorbing layer has a gradient in composition over at least a portion of its thickness.

20. An adapted LED according to claim 1, wherein the light absorbing layer comprises a II-VI semiconductor.

21. An adapted LED according to claim 1, wherein the light absorbing layer comprises a CdMgZnSe alloy.

22. An adapted LED according to claim 1, wherein the light absorbing layer comprises ZnSe, CdSe, MgSe, ZnS, or MgS, or an alloy thereof.

23. An adapted LED according to claim 1, wherein the light absorbing layer comprises ZnSe, BeSe, or MgSe, or an alloy thereof.

24. An adapted LED according to claim 1, wherein the re-emitting semiconductor construction is capable of converting at least a portion of light emitted by the LED to a longer wavelength light.

25. An adapted LED according to claim 1, wherein the LED is bonded to the re-emitting semiconductor construction.

26. An adapted LED according to claim 1 further comprising a refractive index matching layer.

27. An adapted LED according to claim 1 further comprising a support layer substantially transparent to light emitted by the LED and the re-emitting semiconductor construction.

28. An adapted LED according to claim 27 having multiple potential wells separated by the support layer.

29. An adapted LED according to claim 27 having multiple absorbing layers separated by the support layer.

30. An adapted LED according to claim 27, wherein the support layer comprises a Cd(Mg)ZnSe alloy.

31. An adapted LED according to claim 27, wherein the support layer comprises ZnSe, CdSe, MgSe, ZnS, or MgS, or an alloy thereof.

32. An adapted LED according to claim 27, wherein the support layer comprises ZnSe, BeSe, or MgSe, or an alloy thereof.

33. An adapted LED according to claim 27, wherein the support layer is an outermost layer of the re-emitting semiconductor construction.

34. An adapted LED according to claim 1 having multiple potential wells separated by the absorbing layer.

35. An illumination device comprising an adapted LED according to claim 1.