Light-emitting diode
View Patent ↗A light-emitting diode, comprises an active layer for emitting a light ray; an upper semiconductor stack on the active layer, wherein the upper semiconductor stack comprises a window layer; a reflector; and a lower semiconductor stack between the active layer and the reflector; wherein the thickness of the window layer is small than or equal to 3 μm, and the thickness of the lower semiconductor stack is small than or equal to 1 μm.
1. A light-emitting diode, comprising:
an active layer;
an upper semiconductor stack on the active layer and comprising a window layer; and
a lower semiconductor stack below the active layer and comprising multiple semiconductor layers which combined have a thickness smaller than or equal to 1 μm,
wherein the multiple semiconductor layers comprise a confining layer below the active layer, a cladding layer below the confining layer, a buffer layer below the cladding layer and a lower contact layer below the cladding layer.
2. The light-emitting diode according to claim 1 , wherein the active layer emits a light ray having a peak wavelength and one of the multiple semiconductor layers has a thickness larger than one seventh of the peak wavelength λ in air.
3. The light-emitting diode according to claim 1 , wherein the window layer is thicker than the lower semiconductor stack.
4. The light-emitting diode according to claim 1 , wherein the lower contact layer comprises GaP.
5. The light-emitting diode according to claim 1 , wherein the active layer emits a light ray having a peak wavelength and the lower contact layer has a thickness smaller than one seventh of the peak wavelength.
6. The light-emitting diode according to claim 1 , wherein each of the multiple semiconductor layers has a refractive index between 2.9 and 3.5.
7. The light-emitting diode according to claim 1 , wherein the window layer comprises (Al B Ga 1-g ) 0.5 As 0.5 , 0.25<g<0.35 or (Al d Ga 1-d ) 0.5 In 0.5 P, 0.65<d<0.75.
8. The light-emitting diode according to claim 1 , further comprising a reflector below the lower semiconductor stack and comprising an insulating layer contacting the lower semiconductor stack, wherein the insulating layer has a refractive index lower than 1.5.
9. The light-emitting diode according to claim 8 , wherein the insulating layer comprises SiNx, SiO 2 , MgF 2 , or combination thereof.
10. The light-emitting diode according to claim 8 , wherein the reflector further comprises a transparent conductive layer contacting the lower semiconductor.
11. The light-emitting diode according to claim 8 , wherein a distance between the reflector and the active layer is between 200 nm and 1 μm.
12. The light-emitting diode according to claim 8 , further comprising a substrate and bonding layer adhering the substrate and the reflector.
13. The light-emitting diode according to claim 1 , wherein the active layer emits a light ray having a peak wavelength between 720 nm and 940 nm.
14. The light-emitting diode according to claim 1 , wherein the widow layer has a thickness between 2 μm and 3 μm.
15. The light-emitting diode according to claim 1 , wherein the window layer comprises a roughened surface.
16. The light-emitting diode according to claim 1 , wherein the thickness of the lower semiconductor stack is between 200 nm and 1 μm.
17. The light-emitting diode according to claim 1 , wherein the active layer comprises well layers and barrier layers laminated alternately, and a thickness of the well layer is between 20Å and 100Å.
18. The light-emitting diode according to claim 1 , wherein the thickness of the confining layer is between 80 nm and 300 nm.
19. The light-emitting diode according to claim 1 , wherein the thickness of the cladding layer is between 80 nm and 500 nm.
20. The light-emitting diode according to claim 1 , wherein the thickness of the lower contact layer is between 20 nm and 80 nm.