Light emitting diode
A light emitting diode device may include a carrier, a p-type and n-type semiconductor layers, an active layer, a first electrode and a second electrode is provided. The carrier has a growth surface and at least one nano-patterned structure on the growth surface, in which the carrier includes a substrate and a semiconductor capping layer disposed between the substrate and the n-type semiconductor layer. The n-type semiconductor layer and the p-type semiconductor layer are located over the growth surface of the carrier. The active layer is located between the n-type and p-type semiconductor layers, in which a wavelength λ of light emitted by the active layer is 222 nm≦λ≦405 nm, and a defect density of the active layer is less than or equal to 5×10 10 /cm 2 . The first and second electrodes are respectively connected to the n-type and p-type semiconductor layers. A carrier for carrying a semiconductor layer is also provided.
1. A light emitting diode (LED) device, comprising:
a carrier, having a growth surface and at least one nano-patterned structure on the growth surface, wherein the carrier comprises a substrate and a semiconductor capping layer;
an n-type semiconductor layer and a p-type semiconductor layer, located over the growth surface of the carrier, wherein the semiconductor capping layer is disposed between the substrate and the n-type semiconductor layer;
an active layer located between the n-type semiconductor layer and the p-type semiconductor layer, wherein a wavelength λ of light emitted by the active layer is 222 nm≦λ≦405 nm, and a defect density of the active layer is less than or equal to 5×10 10 /cm 2 ; and
a first electrode and a second electrode, respectively connected to the n-type semiconductor layer and the p-type semiconductor layer.
2. The LED device according to claim 1 , wherein a defect density of the semiconductor capping layer is less than or equal to 1×10 10 /cm 2 .
3. The LED device according to claim 1 , the at least one nano-patterned structure is on a surface of the substrate, and the semiconductor capping layer covers and is in contact with the at least one nano-patterned structure.
4. The LED device according to claim 1 , wherein the substrate has a plane surface, the semiconductor capping layer covers the plane surface, the at least one nano-patterned structure is on a surface of the semiconductor capping layer, and the n-type semiconductor layer covers and is in contact with the at least one nano-patterned structure.
5. The LED device according to claim 1 , wherein the substrate has a patterned surface, the semiconductor capping layer covers the patterned surface, the at least one nano-patterned structure is on a surface of the semiconductor capping layer, and the n-type semiconductor layer covers and is in contact with the at least one nano-patterned structure.
6. The LED device according to claim 1 , wherein a thickness of the semiconductor capping layer is less than or equal to 10 μm, and ranges from 1 μm to 4 μm.
7. The LED device according to claim 1 , wherein a material of the semiconductor capping layer comprises gallium nitride (GaN), aluminum gallium nitride (AlGaN), aluminum nitride (AlN), indium gallium nitride (InGaN) or a combination thereof.
8. The LED device according to claim 1 , wherein the at least one nano-patterned structure comprises a plurality of mesas, and a recess is formed between two adjacent mesas.
9. The LED device according to claim 8 , wherein the mesas of the at least one nano-patterned structure are arranged regularly.
10. The LED device according to claim 8 , wherein the mesas of the at least one nano-patterned structure are arranged randomly.
11. The LED device according to claim 8 , wherein a depth of the recess ranges from 10 nm to 500 nm, and a dimension of the mesa ranges from 10 nm to 800 nm.
12. The LED device according to claim 8 , wherein a dimension w 1 of the mesa and a dimension w 2 of the recess satisfy the following relationship:
0.0125 ≦[w 1 /w 2 ]≦80.
13. The LED device according to claim 1 , wherein a plurality of voids are formed above the recesses or above the mesas between the substrate and the n-type semiconductor layer.
14. The LED device according to claim 13 , wherein each of the voids has a refraction coefficient n2, the substrate has a refraction coefficient n1 and the semiconductor capping layer has a refraction coefficient n3, where n3>n2>n1.
15. The LED device according to claim 8 , further comprising:
a mask layer, covering sidewalls of each mesa and a bottom surface of each recess between the two adjacent mesas.
16. The LED device according to claim 15 , wherein a thickness of the mask layer ranges from 0.1 μm to 2 μm.
17. The LED device according to claim 15 , wherein a material of the mask layer comprises silicon dioxide, silicon nitride or silicon oxynitride.