LED for plant illumination

Patent metadata

Field	Value
Publication number	US-10716262-B2
Application number	US-201816194287-A
Country	US
Kind code	B2
Filing date	Nov 16, 2018
Priority date	Mar 7, 2013
Publication date	Jul 21, 2020
Grant date	Jul 21, 2020

Abstract

An epitaxial wafer for plant lighting light-emitting diodes (LED), the epitaxial wafer includes: a growth substrate; a first red-light epitaxial laminated layer; a distributed Bragg reflector (DBR) semiconductor laminated layer; and a second red-light epitaxial laminated layer; wherein: the first red-light epitaxial laminated layer comprises a first N-type ohmic contact layer, a first N-type covering layer, a first light-emitting layer, a first P-type covering layer, and a first P-type ohmic contact layer; and the second red-light epitaxial laminated layer comprises a second N-type ohmic contact layer, a second N-type covering layer, a second light-emitting layer, a second P-type covering layer, and a second P-type ohmic contact layer.

First claim

The invention claimed is:

1. A light-emitting diode (LED) for plant lighting, comprising:
a first red-light epitaxial laminated layer having a first light-emitting layer; and a second red-light epitaxial laminated layer having a second light-emitting layer; wherein:
a light-emitting area of the first red-light epitaxial laminated layer is less than a light-emitting area of the second red-light epitaxial laminated layer; and
a light emitting wavelength of the first light-emitting layer is longer than a light emitting wavelength of the second light-emitting layer.

2. The LED of claim 1 , further comprising a distributed Bragg reflector (DBR) semiconductor laminated layer between the first red-light epitaxial laminated layer and the second red-light epitaxial laminated layer.

3. The LED of claim 2 , wherein the DBR semiconductor laminated layer is smaller than the light-emitting area of the second red-light epitaxial laminated layer, but larger than the light-emitting area of the first red-light epitaxial laminated layer.

4. The LED of claim 2 , wherein:
a surface of the second red-light epitaxial laminated layer is preset with a light-emitting area and a non-light-emitting area;
the DBR semiconductor laminated layer is formed on the non-light-emitting zone of the second red-light epitaxial laminated layer; and
the first red-light epitaxial laminated layer is formed on the DBR semiconductor laminated layer.

5. The LED of claim 4 , wherein a doping concentration of the DBR semiconductor laminated layer is 5×10 17 to thereby form a high-resistance interface.

6. The LED of claim 4 , wherein the DBR semiconductor laminated layer form a high-resistance interface, when injecting a current to the LED, the DBR semiconductor laminated layer prevents the current from entering into the non-light-emitting area of the second red-light epitaxial laminated layer, but flows as far as possible to the light-emitting area of the second red-light epitaxial laminated layer.

7. The LED of claim 6 , further comprising an electrical coupling structure which electrically connects to the first red-light epitaxial laminated layer and the second red-light epitaxial laminated layer.

8. The LED of claim 7 , wherein:
the first red-light epitaxial laminated layer further includes a first N-type semiconductor layer and a first P-type semiconductor layer;
the second red-light epitaxial laminated layer further includes a second N-type semiconductor layer and a second P-type semiconductor layer; and
the first P-type semiconductor layer electrically connects to the second N-type semiconductor layer via the electrical coupling structure.

9. The LED of claim 8 , further comprising an electrical current diffusion structure disposed over a non-light-emitting area of the second N-type semiconductor layer.

10. The LED of claim 1 , further comprising a high-resistance semiconductor layer between the first red-light epitaxial laminated layer and the second red-light epitaxial laminated layer, and wherein:
a surface of the second red-light epitaxial laminated layer is preset with a light-emitting area and a non-light-emitting area;
the high-resistance semiconductor layer is formed on the non-light-emitting zone of the second red-light epitaxial laminated layer; and
the first red-light epitaxial laminated layer is formed on the high-resistance semiconductor layer.

11. The LED of claim 10 , when injecting a current to the LED, the high-resistance semiconductor layer prevents the current from entering into the non-light-emitting area of the second red-light epitaxial laminated layer, but flows as far as possible to the light-emitting area of the second red-light epitaxial laminated layer.

12. The LED of claim 11 , further comprising an electrical coupling structure which electrically connects to the first red-light epitaxial laminated layer and the second red-light epitaxial laminated layer.

13. The LED of claim 12 , wherein:
the first red-light epitaxial laminated layer further includes a first N-type semiconductor layer and a first P-type semiconductor layer;
the second red-light epitaxial laminated layer further includes a second N-type semiconductor layer and a second P-type semiconductor layer; and
the first P-type semiconductor layer electrically connects to the second N-type semiconductor layer via the electrical coupling structure.

14. The LED of claim 13 , further comprising an electrical current diffusion structure disposed over a non-light-emitting area of the second N-type semiconductor layer.

15. The LED of claim 1 , wherein a light emitting wavelength of the first light-emitting layer is 710 nm-750 nm, and a light emitting wavelength of the second light-emitting layer is 640 nm-680 nm.

16. The LED of claim 15 , wherein the light emitting wavelength of the first light-emitting layer is 730 nm, and the light emitting wavelength of the second light-emitting layer is 660 nm.

17. The LED of claim 1 , wherein the light-emitting area of the first red-light epitaxial laminated layer is one-third of the light-emitting area of the second red-light epitaxial laminated layer.

18. A fabrication method of a plant lighting light-emitting diode (LED), the method comprising:
providing a LED epitaxial wafer, which comprising: a first red-light epitaxial laminated layer includes a first light-emitting layer, and a second red-light epitaxial laminated layer includes a second light-emitting layer, wherein a light emitting wavelength of the first light-emitting layer is longer than a light emitting wavelength of the second light-emitting layer;
defining a first light-emitting zone and a second light-emitting zone on the epitaxial wafer surface; and
removing the red-light epitaxial laminated layer of the second light-emitting area to forming a first light-emitting area for the first red-light epitaxial laminated layer and a second light-emitting area for the second red-light epitaxial laminated layer;
where the first light-emitting area is less than the second light-emitting area.

19. The method of claim 18 , wherein the epitaxial wafer further comprising a DBR semiconductor laminated layer between the first red-light epitaxial laminated layer and the second red-light epitaxial laminated layer, and also removing the DBR semiconductor laminated layer of the second light-emitting area.

20. The method of claim 19 , further comprising:
forming an electrical coupling structure which electrically connects to the first red-light epitaxial laminated layer and the second red-light epitaxial laminated layer.

Assignees

• Xiamen Sanan Optoelectronics Technology Co Ltd

Inventors

• Wu Chaoyu
• Wu Chun-I
• Huang Junkai
• Wang Duxiang
• Lin Hongliang
• Huang Yi-Jui
• Tao Ching-Shan

Classifications

• H10H20/814

  having reflecting means, e.g. semiconductor Bragg reflectors · 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

• H10H20/812

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

• A01G7/045 Primary

  with electric lighting · CPC title

• Y02P60/14

  Measures for saving energy, e.g. in green houses · CPC title