Methods and devices for light extraction from a Group III-nitride volumetric LED using surface and sidewall roughening
View Patent ↗Embodiments of the present disclosures are directed to improved approaches for achieving high-performance light extraction from a Group III-nitride volumetric LED chips. More particularly, disclosed herein are techniques for achieving high-performance light extraction from a Group III-nitride volumetric LED chip using surface and sidewall roughening.
1. A light emitting diode comprising:
a gallium and nitrogen containing substrate comprising a surface region;
an n-type epitaxial material overlying the surface region;
one or more active regions overlying the n-type epitaxial material;
a p-type epitaxial material overlying the one or more active regions;
a first electrode coupled to the n-type epitaxial material, to the substrate, or to both the n-type epitaxial material and to the substrate;
a second electrode coupled to the p-type epitaxial material; and
at least three lateral surface regions extending from a top surface of the light emitting diode to a base of the light emitting diode;
wherein at least one of the at least three lateral surface regions comprises a first portion characterized by a one-dimensional surface roughness.
2. The light emitting diode of claim 1 , wherein the one-dimensional surface roughness is characterized by striations extending from the top surface toward the base.
3. The light emitting diode of claim 1 , wherein the one-dimensional surface roughness is characterized by an average lateral size from 1 μm to 10 μm.
4. The light emitting diode of claim 1 , wherein the one-dimensional surface roughness is characterized by an average vertical size from 100 nm and 10 μm.
5. The light emitting diode of claim 1 , wherein the first portion extends from the top surface toward the base.
6. The light emitting diode of claim 1 , wherein the at least one of the at least three lateral surface regions comprises a second portion extending from the first portion to the base.
7. The light emitting diode of claim 1 , wherein the at least three lateral surface regions comprise an a-plane surface.
8. The light emitting diode of claim 1 , wherein the top surface comprises a surface roughness.
9. The light emitting diode of claim 1 , wherein the light emitting diode is characterized by a vertical to horizontal aspect ratio from 1:20 to 1:1.
10. The light emitting diode of claim 1 , wherein the light emitting diode has the shape of a prism with a triangular base.
11. The light emitting diode of claim 1 , wherein the at least three lateral surface regions are at an angle with respect to the top surface and the base.
12. The light emitting diode of claim 1 , wherein,
the top surface is triangular;
the base is triangular; and
the at least three lateral surface regions comprise three lateral surface regions.
13. The light emitting diode of claim 1 , wherein the light emitting diode has a thickness from 5 μm to 20 μm.
14. The light emitting diode of claim 1 , wherein the one-dimensional surface roughness is configured to extract a substantial portion of electromagnetic radiation derived from the one or more active regions.
15. The light emitting diode of claim 1 , wherein the one or more active regions comprises two or more of indium, gallium, aluminum, and nitrogen.
16. The light emitting diode of claim 1 , wherein the at least one lateral surface region is configured in a non-polar orientation.
17. The light emitting diode of claim 1 , wherein the at least one lateral surface region is configured in a semi-polar orientation.
18. The light emitting diode of claim 1 , wherein the at least one lateral surface region is configured in a polar orientation.
19. The light emitting diode of claim 1 , wherein the at least one lateral surface region is misaligned with a crystallographic plane of the gallium and nitrogen containing substrate.
20. The light emitting diode of claim 1 , wherein the at least one lateral surface region is misaligned within +/−20 degrees with respect to a crystallographic plane of the gallium and nitrogen containing substrate.
21. The light emitting diode of claim 2 , wherein the striations are characterized by a distance of 1 μm to 5 μm.
22. The light emitting diode of claim 6 , wherein the second portion is characterized by a two-dimensional surface roughness.
23. The light emitting diode of claim 8 , wherein the surface roughness ranges from about 80 nm to about 10,000 nm.
24. The light emitting diode of claim 8 , wherein the top surface roughness is configured to extract a substantial portion of electromagnetic radiation derived from the one or more active regions.
25. The light emitting diode of claim 11 , wherein the angle is from 1 degrees to 20 degrees.
26. The light emitting diode of claim 22 , wherein the two-dimensional surface roughness is characterized by a feature size on the order of 1 μm to 2 μm.
27. The light emitting diode of claim 22 , wherein the two-dimensional surface roughness ranges from about 80 nm to about 10,000 nm.
28. A light emitting diode comprising:
a gallium and nitrogen containing substrate comprising a surface region;
an n-type epitaxial material overlying the surface region;
one or more active regions overlying the n-type epitaxial material;
a p-type epitaxial material overlying the one or more active regions;
a first electrode coupled to the n-type epitaxial material, to the substrate, or to both the n-type epitaxial material and to the substrate;
a second electrode coupled to the p-type epitaxial material;
a triangular top surface comprising a top textured surface;
a triangular base; and
three lateral surface regions extended from the top surface to the base,
wherein a portion of each of the three lateral surface regions is characterized by a one-dimensional surface roughness.