Light emitting devices with improved extraction efficiency

• US 7,166,870 B2
• Filed: 11/19/2004
• Issued: 01/23/2007
• Est. Priority Date: 04/15/2003
• Status: Active Grant

• Current Assignee: Formosa Epitaxy Incorporated (Epistar Corporation)
• Original Assignee: Luminus Devices Incorporated (Sanan Optoelectronics Company Limited)
• Inventors: Erchak, Alexei A., Luo, Chiyan, Lidorikis, Eleftrios
• Primary Examiner(s): Andujar; Leonardo
• Assistant Examiner(s): Wilson; Scott R.
• Application Number:
  US10/993,342
• Publication Number:
  US 20050087757A1
• Time in Patent Office: 795 Days
• Field of Search: None
• US Class Current: 257/86
• CPC Class Codes: H01L 2933/0083 Periodic patterns for optical field-shaping in or on the semiconductor body or semiconductor body package, e.g. photonic bandgap structures
• CPC Class Codes: H01L 33/0093 Wafer bonding; Removal of the growth substrate
• CPC Class Codes: H01L 33/10 with a light reflecting structure, e.g. semiconductor Bragg reflector
• CPC Class Codes: H01L 33/20 with a particular shape, e.g. curved or truncated substrate
• CPC Class Codes: H01L 33/32 containing nitrogen
• CPC Class Codes: H01S 5/11 Comprising a photonic bandgap structure

Abstract

Light-emitting devices, and related components, systems and methods are disclosed.

Claims

1. A light-emitting device, comprising:

a multi-layer stack of materials including a layer of n-doped material, a layer of p-doped material, and a light-generating region; and

a layer of reflective material that is capable of reflecting at least about 50% of light generated by the light-generating region that impinges on the layer of reflective material,

wherein;

a surface of the layer of n-doped material is configured so that light generated by the light-generating region can emerge from the light-emitting device via the surface of the layer of n-doped material;

the surface of the layer of n-doped material has a dielectric function that varies spatially according to a pattern,

the pattern is configured so that light emitted by the surface of the layer of n-doped material has a spectrum of radiation modes, and the spectrum of radiation modes is substantially the same as a characteristic emission spectrum of the light-generating region;

a distance between the layer of p-doped material and the layer of reflective material is less than a distance between the layer of n-doped material and the layer of reflective material; and

the layer of n-doped material is supported by the layer of p-doped material.

2. The light-emitting device of claim 1, wherein the multi-layer stack of materials comprises a multi-layer stack of semiconductor materials.

3. The light-emitting device of claim 1, wherein the n-doped material comprises an n-doped semiconductor material and the p-doped material comprises a p-doped semiconductor material.

4. The light-emitting device of claim 1, wherein the light-generating region is between the layer of n-doped material and the layer of p-doped semiconductor material.

5. The light-emitting device of claim 1, further comprising a support that supports the multi-layer stack of materials.

6. The light-emitting device of claim 1, further comprising a p-ohmic contact layer between the layer of p-doped material and the layer of reflective material.

7. The light-emitting device of claim 1, further including a current-spreading layer between the layer of n-doped material and the light-generating region.

8. The light-emitting device of claim 1, wherein the multi-layer stack of materials comprise semiconductor materials.

9. The light-emitting device of claim 8, wherein the semiconductor materials are selected from the group consisting of III–

V semiconductor materials, organic semiconductor materials and silicon.

10. The light-emitting device of claim 1, wherein the surface of the layer of n-doped material has a dielectric function that varies spatially according to a pattern.

11. The light-emitting device of claim 10, wherein the pattern does not extend into the light-generating region.

12. The light-emitting device of claim 10, wherein the pattern does not extend beyond the layer of n-doped material.

13. The light-emitting device of claim 10, wherein the pattern extends beyond the layer of n-doped material.

14. The light-emitting device of claim 10, wherein the pattern is partially formed of a component selected from the group consisting of holes in the surface of the layer of n-doped material, pillars in the layer of n-doped material, continuous veins in the layer of n-doped material, discontinuous veins in the layer of n-doped material and combinations thereof.

15. The light-emitting device of claim 10, wherein the pattern of variation is selected from the group consisting of nonperiodic patterns, complex periodic patterns, and patterns having an ideal lattice constant and a detuning parameter greater than zero.

16. The light-emitting device of claim 10, wherein the pattern is partially formed of holes in the layer of n-doped material.

17. The light-emitting device of claim 10, wherein the pattern is configured so that light emitted by the surface of the layer of n-doped material has a spectrum of radiation modes, and the spectrum of radiation modes is substantially the same as a characteristic emission spectrum of the light-generating region.

18. The light-emitting device of claim 10, wherein the pattern does extends into the light-generating region.

19. The light-emitting device of claim 1, further comprising electrical contacts configured to inject current into the light-emitting device.

20. The light-emitting device of claim 19, wherein the electrical contacts are configured to vertically inject electrical current into the light-emitting device.

21. The light-emitting device of claim 1, wherein the light-emitting device is selected from the group consisting of light-emitting diodes, lasers, optical amplifiers, and combinations thereof.

22. The light-emitting device of claim 1, wherein the light-emitting device comprises a light emitting diode.

23. The light-emitting device of claim 1, wherein the light-emitting device is selected from the group consisting of OLEDs, flat surface-emitting LEDs, HBLEDs, and combinations thereof.

24. The light-emitting device of claim 1, wherein the surface of the layer of n-doped material is a roughened surface.

25. The light-emitting device of claim 24, wherein the roughened surface is a locally non-planar interface.

26. The light-emitting device of claim 1, wherein the surface of the layer of n-doped material is approximately smooth.

27. The light-emitting device of claim 1, wherein the surface of the layer of n-doped material has a surface smoothness of less than about 5 nm root mean square (rms).

28. A light-emitting device, comprising:

a multi-layer stack of materials including a layer of n-doped material, a layer of p-doped material, and a light-generating region; and

a layer of reflective material that is capable of reflecting at least about 50% of light generated by the light-generating region that impinges on the layer of reflective material,

wherein;

a surface of the layer of n-doped material is configured so that light generated by the light-generating region can emerge from the light-emitting device via the surface of the layer of n-doped material,

the surface of the layer of n-doped material has a dielectric function that varies spatially according to a pattern,

the pattern is a nonperiodic pattern,

a distance between the layer of p-doped material and the layer of reflective material is less than a distance between the layer of n-doped material and the layer of reflective material; and

the layer of n-doped material is supported by the layer of p-doped material.

29. The light emitting device of claim 28, wherein the pattern is partially formed of holes in the layer of n-doped material.

30. A light-emitting device, comprising:

a multi-layer stack of materials including a layer of n-doped material, a layer of p-doped material, and a light-generating region; and

a layer of reflective material that is capable of reflecting at least about 50% of light generated by the light-generating region that impinges on the layer of reflective material,

wherein;

a surface of the layer of n-doped material is configured so that light generated by the light-generating region can emerge from the light-emitting device via the surface of the layer of n-doped material;

a distance between the layer of p-doped material and the layer of reflective material is less than a distance between the layer of n-doped material and the layer of reflective material;

the layer of n-doped material is supported by the layer of p-doped material; and

the surface of the layer of n-doped material has a surface smoothness of less than about 5 nm root mean square (rms).

31. The light emitting device of claim 30, wherein the surface of the layer of n-doped material has a dielectric function that varies spatially according to a pattern.

32. The light emitting device of claim 31, wherein the pattern is partially formed of holes in the layer of n-doped material.