Light emitting device and method of making the same

Patent metadata

Field	Value
Publication number	US-11769858-B2
Application number	US-202217650302-A
Country	US
Kind code	B2
Filing date	Feb 8, 2022
Priority date	Mar 18, 2020
Publication date	Sep 26, 2023
Grant date	Sep 26, 2023

Abstract

A light emitting device for emitting UVC radiation. The device comprises a substrate and a patterned layer. The patterned layer comprises a plurality of mask regions on the substrate. Exposed portions of the substrate are disposed between the mask regions. A plurality of nanostructures are disposed on the exposed portions of the substrate and over the mask regions, the plurality of nanostructures being a single crystal semiconductor and comprising a core tip. An active layer is disposed over the plurality of nanostructures. The active layer is a quantum well structure and comprises at least one material chosen from AIN, AlGaN and GaN. A p-doped layer is disposed over the active layer. Both the active layer and the p-doped layer are conformal to the plurality of nanostructures so as to form an emitter tip over the core tip.

First claim

What is claimed is:

1. A light emitting device for emitting UVC radiation, comprising:
a substrate;
a patterned layer comprising a plurality of mask regions on the substrate, exposed portions of the substrate being disposed between the mask regions;
a plurality of nanostructures disposed on the exposed portions of the substrate and over the mask regions, the plurality of nanostructures being a single crystal semiconductor and comprising angled faces, a c-axis surface parallel to that of the substrate, and a core tip;
an active layer disposed over the angled faces of the plurality of nanostructures, the active layer being a quantum well structure and comprising at least one material chosen from AlN, AlGaN and GaN, the active layer configured to emit UVC radiation during operating of the light emitting device; and
a p-doped layer disposed over the active layer, both the active layer and the p-doped layer being conformal to the plurality of nanostructures so as to form an emitter tip over the core tip.

2. The light emitting device of claim 1 , wherein the substrate comprises at least one semiconductor chosen from silicon, sapphire (Al 2 O 3 ), silicon carbide (SiC), gallium nitride (GaN) and Aluminum Nitride (AlN).

3. The light emitting device of claim 1 , wherein the mask regions comprise at least one material chosen from an insulator and a metal.

4. The light emitting device of claim 1 , wherein the mask regions have a width ranging from about 50 nm to about 1000 nm.

5. The light emitting device of claim 1 , wherein the exposed portions between the mask regions have a width ranging from about 50 nm to about 1000 nm.

6. The light emitting device of claim 1 , wherein the plurality of nanostructures comprise at least one material chosen from AlN, GaN and AlGaN, the material of the plurality of nanostructures being different than the material of the active layer.

7. The light emitting device of claim 1 , wherein the nanostructures have a three-dimensional shape chosen from prisms, nanowires and mesas.

8. The light emitting device of claim 1 , wherein the nanostructures are ridges that are corrugated.

9. The light emitting device of claim 1 , wherein the nanostructures are hexagonal mesas.

10. The light emitting device of claim 1 , wherein nanostructures comprise at least one face having an angle ranging from about 40 degrees to about 90 degrees with respect to an upper surface of the substrate on which they are formed.

11. The light emitting device of claim 1 , wherein the active layer is a multiple quantum well structure comprising at least one AlN layer and at least one AlGaN layer.

12. The light emitting device of claim 1 , wherein the active layer comprises Al x Ga (1−x) N, where x ranges from 0.5 to about 0.9.

13. The light emitting device of claim 1 , wherein the active layer has a thickness ranging from about 1 nm to about 2000 nm.

14. The light emitting device of claim 1 , wherein the light emitting device comprises one or more light emitting diodes, the one or more light emitting diodes being configured to emit radiation having a wavelength ranging from about 200 nm to about 350 nm.

15. The light emitting device of claim 1 , wherein the p-doped layer comprises at least one semiconductor material chosen from AlN, AlGaN and hexagonal Boron Nitride, the material of the p-doped layer being different than the material of the active layer.

16. The light emitting device of claim 1 , wherein the p-doped layer has a graded dopant concentration.

17. The light emitting device of claim 1 , wherein the substrate is a flexible substrate.

18. The light emitting device of claim 1 , wherein the active layer does not include indium.

19. A method of making a UVC light emitting device, the method comprising:
forming a patterned layer comprising a plurality of mask regions on a substrate, wherein exposed portions of the substrate are disposed between the mask regions;
epitaxially growing a plurality of nanostructures on the exposed portions of the substrate and over the mask regions, the plurality of nanostructures comprising angled faces, a c-axis surface parallel to that of the substrate, and a core tip;
epitaxially growing an active layer over the angled faces of the plurality of nanostructures, the active layer being a quantum well structure and comprising at least one material chosen from AlN, AlGaN and GaN, the active layer configured to emit UVC radiation during operating of the light emitting device; and
depositing a p-doped layer over the active layer, both the active layer and the p-doped layer being conformal to the plurality of nanostructures so as to form an emitter tip over the core tip.

20. The method of claim 19 , wherein the substrate comprises at least one semiconductor chosen from silicon, silicon carbide (SiC), sapphire(Al 2 O 3 ), gallium nitride (GaN) and Aluminum Nitride (AlN).

21. The method of claim 19 , wherein the mask regions comprise at least one material chosen from an insulator and a metal.

22. The method of claim 19 , wherein the plurality of nanostructures comprise at least one material chosen from AlN, GaN and AlGaN, the material of the plurality of nanostructures being different than the material of the active layer.

23. The method of claim 19 , wherein the nanostructures have a three-dimensional shape chosen from prisms, nanowires and mesas.

24. The method of claim 19 , wherein the nanostructures are ridges that are corrugated.

25. The method of claim 19 , wherein nanostructures comprise at least one face having an angle ranging from about 40 degrees to about 90 degrees with respect to an upper surface of the substrate on which they are formed.

26. The method of claim 19 , wherein the active layer comprises Al x Ga (1−x) N, where x ranges from 0.5 to about 0.9.

27. The method of claim 19 , wherein the active layer has a thickness ranging from about 1 nm to about 2000 nm.

28. The method of claim 19 , wherein the p-doped layer comprises a p-type dopant, the method further comprising introducing the p-type dopant by a polarization doping technique.

29. The method of claim 19 , further comprising removing the substrate and replacing it with a second substrate.

30. The method of making a UVC light emitting device of claim 19 , wherein the active layer does not include indium.

31. A method of sanitizing a surface, the method comprising:
contacting the surface with UVC radiation emitted from a light emitting device, the light emitting device comprising:
a substrate;
a patterned layer comprising a plurality of mask regions on the substrate, exposed portions of the substrate being disposed between the mask regions;
a plurality of nanostructures disposed on the exposed portions of the substrate and over the mask regions, the plurality of nanostructures being a single crystal semiconductor and comprising angled faces, a c-axis surface parallel to that of the substrate, and a core tip;
an active layer disposed over the angled faces of the plurality of nanostructures, the active layer being a quantum well structure and comprising at least one material chosen from AlN, AlGaN and GaN, the active layer configured to emit UVC radiation during operating of the light emitting device; and
a p-doped layer disposed over the active layer, both the active layer and the p-doped layer being confo

Assignees

• Boeing Co

Inventors

• Cui Shanying
• Kim Danny

Classifications

• H10H20/825

  containing nitrogen, e.g. GaN · CPC title

• H10H20/812 Primary

  within the light-emitting regions, e.g. having quantum confinement structures · CPC title

• H10H20/0137

  the light-emitting regions comprising nitride materials · CPC title

• H10H20/821 Primary

  of the light-emitting regions, e.g. non-planar junctions · CPC title

• H10H20/813

  having a plurality of light-emitting regions, e.g. multi-junction LEDs or light-emitting devices having photoluminescent regions within the bodies · CPC title