Nitride light emitting diode and fabrication method thereof
A nitride light-emitting diode including: a substrate with sub-micro patterns over the surface, which is divided into a growth region and a non-growth region; a growth blocking layer, formed in the non-growth region of the substrate for blocking epitaxial growth in the non-growth region of the substrate; a light-emitting epitaxial layer, comprising an n-type layer, a light-emitting layer and a p-type layer, formed in the growth region of the substrate, which extends to the non-growth region through lateral epitaxy and covers the growth blocking layer; wherein, the refractive index of the growth blocking layer is less than that of the light-emitting epitaxial layer and the growth blocking layer forms undulating morphology along the sub-micro patterns of the substrate, thus increasing light extraction interface of LED, generating refractive index difference between the light-emitting epitaxial layer and the light extraction interface and improving light extraction efficiency.
1. A nitride light-emitting diode, comprising:
a substrate having a surface with sub-micro patterns, including a growth region and a non-growth region;
a growth blocking layer, formed in the non-growth region of the substrate for blocking epitaxial growth in the non-growth region of the substrate;
a light-emitting epitaxial layer, comprising an n-type layer, a light-emitting layer, and a p-type layer, formed in the growth region of the substrate, extending to the non-growth region through lateral epitaxy and covering the growth blocking layer;
wherein:
a refractive index of the growth blocking layer is less than that of the light-emitting epitaxial layer, and the growth blocking layer forms undulating morphology along the sub-micro patterns of the substrate, thereby increasing a light extraction interface of light-emitting diode and generating a refractive index difference between the light-emitting epitaxial layer and the light extraction interface; and
an angle α between an undulated surface and a plane surface of the growth blocking layer is formed to be 40°-70° to thereby increase light scattering probability and thereby improving the light extraction efficiency.
2. The nitride light-emitting diode of claim 1 , wherein a gap exists between the growth blocking layer and the light-emitting epitaxial layer.
3. The nitride light-emitting diode of claim 1 , wherein a distance h from top to bottom of the growth blocking layer is 200 nm-900 nm.
4. The nitride light-emitting diode of claim 1 , wherein a refractive index X of the growth blocking layer meets conditions including: substrate<X<light-emitting epitaxial layer, thereby increasing a refractive index difference of the light extraction interface.
5. The nitride light-emitting diode of claim 1 , wherein a refractive index X of the growth blocking layer meets conditions including: X<substrate<light-emitting epitaxial layer, thereby increasing refractive index difference of the light extraction interface.
6. The nitride light-emitting diode of claim 1 , wherein the growth blocking layer comprises a series of discrete growth blocking material modules, appearing in a block-shaped or band-shaped distribution.
7. The nitride light-emitting diode of claim 1 , wherein the growth blocking layer comprises an oxide coating or a nitride coating.
8. A nitride light-emitting diode fabrication method, comprising:
providing a substrate having a surface with sub-micro patterns, including a growth region and a non-growth region;
forming a growth blocking layer in the non-growth region of the substrate for blocking epitaxial growth in the non-growth region of the substrate;
growing a light-emitting epitaxial layer, comprising a n-type layer, a light-emitting layer, and a p-type layer in the growth region of the substrate, extending to the non-growth region through lateral epitaxy and covering the growth blocking layer;
wherein:
a refractive index of the growth blocking layer is less than that of the light-emitting epitaxial layer, and the growth blocking layer forms undulating morphology along the sub-micro patterns of the substrate, thereby increasing a light extraction interface of light-emitting diode, generating a refractive index difference between the light-emitting epitaxial layer and the light extraction interface and improving light extraction efficiency; and
an angle α between an undulated surface and a plane surface of the growth blocking layer is formed to be 40°-70° to thereby increase light scattering probability and thereby improving the light extraction efficiency.
9. A lighting or display system, comprising a plurality of light-emitting diodes, each light-emitting diode comprising:
a substrate having a surface with sub-micro patterns, including a growth region and a non-growth region;
a growth blocking layer, formed in the non-growth region of the substrate for blocking epitaxial growth in the non-growth region of the substrate;
a light-emitting epitaxial layer, comprising a n-type layer, a light-emitting layer, and a p-type layer, formed in the growth region of the substrate, extending to the non-growth region through lateral epitaxy and covering the growth blocking layer;
wherein:
a refractive index of the growth blocking layer is less than that of the light-emitting epitaxial layer, and the growth blocking layer forms undulating morphology along the sub-micro patterns of the substrate, thereby increasing a light extraction interface of light-emitting diode and generating a refractive index difference between the light-emitting epitaxial layer and the light extraction interface; and
an angle α between an undulated surface and a plane surface of the growth blocking layer is formed to be 40°-70° to thereby increase light scattering probability and thereby improving the light extraction efficiency.
10. The system of claim 9 , wherein a gap exists between the growth blocking layer and the light-emitting epitaxial layer.
11. The system of claim 9 , wherein a distance h from top to bottom of the growth blocking layer is 200 nm-900 nm.
12. The system of claim 9 , wherein a refractive index X of the growth blocking layer meets conditions including: substrate<X<light-emitting epitaxial layer, thereby increasing a refractive index difference of the light extraction interface.
13. The system of claim 9 , wherein a refractive index X of the growth blocking layer meets conditions including: X<substrate<light-emitting epitaxial layer, thereby increasing refractive index difference of the light extraction interface.
14. The system of claim 9 , wherein the growth blocking layer comprises a series of discrete growth blocking material modules, appearing in a block-shaped or band-shaped distribution.
15. The system of claim 9 , wherein the growth blocking layer comprises an oxide coating or a nitride coating.
16. The nitride light-emitting diode of claim 1 , wherein the angle α is about 60°.
17. The system of claim 9 , wherein the angle α is about 60°.