LIGHT EMITTING DEVICE AND METHOD OF FABRICATING THE SAME

• US 20120132888A1
• Filed: 11/28/2011
• Published: 05/31/2012
• Est. Priority Date: 11/26/2010
• Status: Active Grant

• Current Assignee: Seoul Viosys Co., Ltd. (Seoul Semiconductor Co., Ltd.)
• Original Assignee: Seoul Optodevice Company Limited (Seoul Semiconductor Co., Ltd.)
• Inventors: KIM, Hwa Mok, KWAK, Woo Chul, AN, Soon Ho, KIM, Eun Jin, SONG, Jae Hoon
• Granted Patent: US 8,748,864 B2
• Time in Patent Office: Days
• US Class Current: 257/13
• CPC Class Codes: B82Y 20/00 Nanooptics, e.g. quantum optics or photonic crystals
• CPC Class Codes: B82Y 30/00 Nanotechnology for materials or surface science, e.g. nanocomposites
• CPC Class Codes: H01L 2933/0091 Scattering means in or on the semiconductor body or semiconductor body package H01L33/22 takes precedence
• 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 33/18 within the light emitting region
• CPC Class Codes: H01L 33/38 with a particular shape
• CPC Class Codes: H01L 33/502 Wavelength conversion materials

Abstract

A light emitting device includes a metal backing layer, a reflective electrode layer disposed on the metal backing layer, and a plurality of nanorods disposed on the reflective electrode layer. Each nanorod includes a p-semiconductor layer, an active layer, and an n-semiconductor layer, which are sequentially stacked on the reflective electrode layer. The light emitting device further includes an anti-reflection electrode layer disposed on the nanorods, and quantum dots disposed between the nanorods. The method includes sequentially growing the n-semiconductor layer, the active layer, and the p-semiconductor layer on a substrate; forming the nanorods by etching the p-semiconductor layer using a mask pattern; sequentially forming the reflective electrode layer and the metal backing layer on the p-semiconductor layer and then removing the substrate; disposing quantum dots between the nanorods; and forming the anti-reflection electrode layer on the nanorods.

Claims

1. A light emitting device comprising:

a metal layer;

a reflective layer disposed on the metal layer;

a plurality of nanorods disposed on the reflective layer in a matrix configuration such that the nanorods are spaced apart from one another, wherein each of the nanorods comprises a p-semiconductor layer, an active layer, and an n-semiconductor layer, which are sequentially stacked on the reflective layer;

an anti-reflection layer disposed on the nanorods; and

quantum dots disposed between the nanorods.

2. The light emitting device of claim 1, wherein the quantum dots comprise a direct band gap material having a band gap of 1.0 eV or more.

3. The light emitting device of claim 2, wherein the quantum dots comprise a material selected from the group consisting of ZnSe, ZnS, CdSe, CdS, and InP.

4. The light emitting device of claim 1, further comprising a filler disposed between the nanorods, wherein the filler comprises a material selected from the group consisting of spin-on glass, polyimide, polystyrene, and polycarbonate.

5. The light emitting device of claim 1, wherein some quantum dots are attached to a surface of the active layer of the nanorod.

6. The light emitting device of claim 1, wherein the quantum dots have capping ligand or surfactant provided on surfaces thereof.

7. The light emitting device of claim 1, wherein the nanorods are spaced apart from one another at an interval of 1 μ

m or less.

8. The light emitting device of claim 1, wherein the nanorods have a diameter of 1 μ

m or less.

9. The light emitting device of claim 1, wherein the nanorods have lengths ranging from 500 nm to 4 μ

m.

10. A light emitting device comprising:

a substrate;

an n-semiconductor layer disposed on the substrate, wherein the n-semiconductor layer has rods on a portion thereof, the rods being spaced apart from one another in a matrix configuration;

a plurality of nanorods, wherein each of the nanorods comprises an active layer and a p-semiconductor layer, which are sequentially stacked on a corresponding rod of the n-semiconductor;

a transparent electrode layer disposed on the nanorods; and

quantum dots disposed between the nanorods.

11. The light emitting device of claim 10, wherein the quantum dots comprise a direct band gap material having a band gap of 1.0 eV or more.

12. The light emitting device of claim 11, wherein the quantum dots comprise a material selected from the group consisting of ZnSe, ZnS, CdSe, CdS, and InP.

13. The light emitting device of claim 10, further comprising a filler disposed between the nanorods, wherein the filler comprises a material selected from the group consisting of spin-on glass, polyimide, polystyrene, and polycarbonate.

14. The light emitting device of claim 10, wherein some quantum dots are attached to a surface of the active layer of the nanorod.

15. The light emitting device of claim 10, wherein the quantum dots have capping ligand or surfactant provided on surfaces thereof.

16. The light emitting device of claim 10, wherein the nanorods are spaced apart from one another at an interval of 1 μ

m or less.

17. The light emitting device of claim 10, wherein the nanorods have a diameter of 1 μ

m or less.

18. The light emitting device of claim 10, wherein the nanorods have lengths ranging from 500 nm to 4 μ

m.

19. A method of fabricating a light emitting device, comprising:

sequentially growing an n-semiconductor layer, an active layer, and a p-semiconductor layer on a substrate;

forming a plurality of nanorods by etching the p-semiconductor layer, such that a part of the substrate is exposed, using a mask pattern, the mask pattern having pattern elements spaced apart from one another in a matrix configuration;

sequentially forming a reflective layer and a metal layer on the p-semiconductor layer and then removing the substrate;

disposing quantum dots between the nanorods; and

forming an anti-reflection layer on the nanorods.

20. The method of claim 19, wherein etching the p-semiconductor layer is conducted using the mask pattern comprising a material selected from the group consisting of SiO₂, anodic aluminum oxide, and metal.

21. The method of claim 19, wherein disposing quantum dots between the nanorods comprises dispersing the quantum dots in a solvent and disposing the quantum dots between the nanorods.

22. The method of claim 21, wherein the solvent is acetone or alcohol.

23. The method of claim 19, wherein disposing quantum dots between the nanorods comprises converting ligand on surfaces of the quantum dots by dispersing the quantum dots in a mixture solution of chloroform and tetramethyl ammonium hydroxide and adding oleic acid and mercaptopropionic acid to the solution in which the quantum dots are dispersed.

24. The method of claim 21, further comprising, after disposing quantum dots between the nanorods:

evaporating the solvent through heat treatment; and

filling space between the nanorods with a material selected from the group consisting of spin-on glass, polyimide, polystyrene, and polycarbonate.

25. The method of claim 19, wherein disposing quantum dots between the nanorods comprises attaching the quantum dots to a surface of the active layer.

26. A method of fabricating a light emitting device, comprising:

sequentially growing an n-semiconductor layer, an active layer, and a p-semiconductor layer on a substrate;

forming a plurality of nanorods by etching the p-semiconductor layer using a mask pattern such that the active layer is exposed, the mask pattern having pattern elements spaced apart from one another in a matrix configuration;

disposing quantum dots between the nanorods; and

forming a transparent electrode layer on the nanorods.

27. The method of claim 26, wherein etching the p-semiconductor layer is conducted using the mask pattern comprising a material selected from the group consisting of SiO₂, anodic aluminum oxide, and metal.

28. The method of claim 26, wherein disposing quantum dots between the nanorods comprises dispersing the quantum dots in a solvent and disposing the quantum dots between the nanorods.

29. The method of claim 28, wherein the solvent is acetone or alcohol.

30. The method of claim 26, wherein disposing quantum dots between the nanorods comprises converting ligand on surfaces of the quantum dots by dispersing the quantum dots in a mixture solution of chloroform and tetramethyl ammonium hydroxide and adding oleic acid and mercaptopropionic acid to the solution in which the quantum dots are dispersed.

31. The method of claim 28, further comprising, after disposing quantum dots between the nanorods:

evaporating the solvent through heat treatment; and

filling space between the nanorods with a material selected from the group consisting of spin-on glass, polyimide, polystyrene, and polycarbonate.

32. The method of claim 26, wherein disposing quantum dots between the nanorods comprises attaching the quantum dots to a surface of the active layer.