LED FOR PLANT ILLUMINATION

• US 20170250311A1
• Filed: 05/14/2017
• Published: 08/31/2017
• Est. Priority Date: 03/07/2013
• Status: Active Grant

• Current Assignee: Quanzhou Sanan Semiconductor Technology Co., Ltd. (Sanan Optoelectronics Company Limited)
• Original Assignee: Xiamen Sanan Optoelectronics Technology Company Limited (Sanan Optoelectronics Company Limited)
• Inventors: LIN, Hongliang, WU, Chaoyu, HUANG, Yi-Jui, WU, Chun-I, TAO, Ching-Shan, HUANG, Junkai, WANG, Duxiang
• Granted Patent: US 10,154,626 B2
• Time in Patent Office: Days
• CPC Class Codes: A01G 7/045 with electric lighting
• CPC Class Codes: H01L 33/06 within the light emitting region, e.g. quantum confinement structure or tunnel barrier
• 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 33/10 with a light reflecting structure, e.g. semiconductor Bragg reflector
• CPC Class Codes: Y02P 60/14 Measures for saving energy, e.g. in green houses

Abstract

A light-emitting diode (LED) for plant illumination includes a substrate, and a PN-junction light-emitting portion over the substrate. The light-emitting portion has a strained light-emitting layer with a component formula of Ga_XIn_(1-X)As_YP_(1-Y) (0<X<1 and 0<Y<1), and a barrier layer, forming a 2˜40-pair alternating-layer structure with the strained light-emitting layer.

Claims

1. A light-emitting diode (LED) comprising:

a PN junction light-emitting portion; and

a window layer substantially transparent to light emitted from the light-emitting portion and also configured to have a current spreading function;

wherein the PN junction light-emitting portion comprises a strained light-emitting layer with a component formula of Ga_XIn_(1-X)As_YP_(1-Y), 0<

X<

1 and 0<

Y≦

0.05 such that the light is suitable for plant illumination.

2. The LED of claim 1, wherein the PN junction light-emitting portion further comprises a barrier layer, forming an alternating-layer structure with the strained light-emitting layer, wherein the alternating-layer structure comprises 2-40 pairs, each pair comprising the strained light-emitting layer and the barrier layer, and wherein the component formula and the alternating-layer structure are selected such that a light-emitting efficiency is improved by 50%-100%.

3. The LED of claim 2, wherein each pair of the alternating-layer structure is 5-100 nm thick;

and the LED has an output power of at least 202.2 mW for a 42×

42 mil quaternary LED element structure and a 350 mA forward current flow.

4. The LED of claim 2, wherein the barrier layer has a component formula of (Al_AGa_1-A)_BIn_(1-B)P (0.3≦

A≦

1 and 0<

B<

1).

5. The LED of claim 1, wherein the window layer comprises a GaP window layer over the PN junction light-emitting portion.

6. The LED of claim 1, wherein a peak light-emitting wavelength of the strained light-emitting layer is 650-750 nm.

7. The LED of claim 1, wherein a peak light-emitting wavelength of the strained light-emitting layer is 700-750 nm.

8. The LED of claim 1, wherein Y is about 0.01.

9. The LED of claim 1, further comprising a barrier layer of (Al_AGa_1-A)_BIn_(1-B)P to reduce compression strain, wherein, 0.5<

B≦

0.52.

10. The LED of claim 9, wherein a plurality of the barrier layers and a plurality of the strained light-emitting layers form a multiple quantum well (MQW) structure.

11. The LED of claim 10, wherein b is about 0.52.

12. The LED of claim 11, wherein a total tension strain of the MQW is 100-200 ppm.

13. The LED of claim 12, wherein a total thickness of the MQW is about 360 nm.

14. An epitaxial wafer for a plant lighting light-emitting diode (LED), comprising:

a PN junction light-emitting portion; and

a window layer substantially transparent to light emitted from the light-emitting portion and also configured to have a current spreading function;

wherein;

the PN junction light-emitting portion comprises a strained light-emitting layer with a component formula of Ga_XIn_(1-X)As_YP_(1-Y), 0<

X<

1 and 0<

Y≦

0.05 such that the light is suitable for plant illumination;

the PN junction light-emitting portion comprises;

a first red-light epitaxial laminated layer;

a 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.

15. The epitaxial wafer of claim 14, wherein a doping concentration of the DBR semiconductor laminated layer is ≦

5×

10¹⁷ to thereby form a high resistance interface.

16. The epitaxial wafer of claim 14, 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.

17. The epitaxial wafer of claim 16, 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.

18. The epitaxial wafer of claim 14, further comprising an etching stop layer between the DBR semiconductor laminated layer and the second red-light epitaxial laminated layer.

19. A light-emitting system for plant lighting, comprising a plurality of light-emitting diode (LED) chips, each chip comprising:

a PN junction light-emitting portion; and

a window layer substantially transparent to light emitted from the light-emitting portion and also configured to have a current spreading function;

wherein;

the PN junction light-emitting portion comprises a strained light-emitting layer with a component formula of Ga_XIn_(1-X)As_YP_(1-Y), 0<

X<

1 and 0<

Y≦

0.05 such that the light is suitable for plant illumination;

the PN junction light-emitting portion comprises;

a first red-light epitaxial laminated layer;

a DBR semiconductor laminated layer;

a second red-light epitaxial laminated layer; and

a conductive bonding substrate;

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;

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;

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;

the first N-type ohmic contact layer is provided with a first electrode;

between the first P-type ohmic contact layer and the second N-type ohmic contact layer is provided with an electronic-connected structure; and

the second P-type ohmic contact layer is provided with a second electrode.

20. The system of claim 19, wherein:

a doping concentration of the DBR semiconductor laminated layer is ≦

5×

10¹⁷ to thereby form a high resistance interface;

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;

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 area of the second red-light epitaxial laminated layer;

an area of the DBR semiconductor laminated layer is less 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; and

the non-light-emitting area of the second N-type ohmic contact layer is provided with an electric diffusion structure.