Light-emitting diode and fabrication method thereof
A light emitting diode includes: a substrate of front and back main surfaces; a V-shaped groove, which has a reflecting surface, formed over front surface of the conductive substrate; a light-emitting epitaxial layer, the margin of which has its vertical projection between the bottom and the inner margin of the V-shaped groove, formed over the substrate, so that light emitted from the light-emitting epitaxial layer margin is incident to the mirror surface of the V-shaped groove and emits outwards. This structure can effectively improve extraction efficiency of device and control path of light at peripheral region of the light-emitting epitaxial layer.
1. A method of fabricating a light-emitting diode, the method comprising:
forming a light-emitting epitaxial layer over a substrate; and
forming at least one V-shaped groove having a reflecting surface over the substrate;
wherein a vertical projection of a peripheral region of the light-emitting epitaxial layer margin is between a bottom and an inner side portion of the V-shaped groove such that light emitted from the light-emitting epitaxial layer margin is incident upon the reflecting surface of the V-shaped groove structure and reflected outwards.
2. The method of claim 1 , wherein the V-shaped groove is formed at a front surface of the substrate, and wherein said projection is formed by coupling the light-emitting epitaxial layer to the substrate.
3. The method of claim 2 , wherein an angle between two side walls of the V-shaped groove is about 90 degrees such that light emitted at a vertical direction is reflected by the V-shaped groove and emits vertically after a parallel displacement outwards.
4. The method of claim 2 , wherein an angle between two side walls of the V-shaped groove formed is an obtuse angle such that light emitted at a vertical direction is reflected by the V-shaped groove and emits outwards, thereby expanding a light emitting angle.
5. The method of claim 2 , further comprising forming a reflecting structure between the light-emitting epitaxial layer and the substrate, wherein a vertical projection of the reflecting structure is at an inner side of the V-shaped groove.
6. A light-emitting diode formed using a method comprising:
forming a light-emitting epitaxial layer over a substrate; and
forming at least one V-shaped groove having a reflecting surface over the substrate;
wherein a vertical projection of a peripheral region of the light-emitting epitaxial layer margin is between a bottom and an inner side portion of the V-shaped groove such that light emitted from the light-emitting epitaxial layer margin is incident upon the reflecting surface of the V-shaped groove structure and reflected outwards,
the light-emitting diode comprising:
the substrate having front and back main surfaces, and the at least one V-shaped groove having the reflecting surface formed over the front main surface of the substrate;
the light-emitting epitaxial layer over the substrate, wherein the peripheral region of the light-emitting epitaxial layer has the vertical projection between a bottom and an inner portion of the V-shaped groove, such that light emitted from the light-emitting epitaxial layer peripheral region is incident upon the reflecting surface of the V-shaped groove and reflected outwards.
7. The light-emitting diode of claim 6 , wherein an optical path of the light emitted from the peripheral region of the light-emitting epitaxial layer is adjusted by the V-shaped groove.
8. The light-emitting diode of claim 7 , wherein an angle between two side walls of the V-shaped groove is about 90 degrees such that light emitted at a vertical direction is reflected by the V-shaped groove and emits vertically after a parallel displacement outwards.
9. The light-emitting diode of claim 8 , wherein: the V-shaped groove has a depth of about 5-20 μm.
10. The light-emitting diode of claim 7 wherein an angle between two side walls of the V-shaped groove is an obtuse angle such that light emitted at a vertical direction is reflected by the V-shaped groove and emits outwards, thereby expanding a light emitting angle.
11. The light-emitting diode of claim 6 , wherein a reflecting structure is formed between the substrate and the light-emitting epitaxial layer, and wherein a vertical projection of the reflecting structure is at an inner side of the V-shaped groove.
12. The light-emitting diode of claim 11 , wherein the reflecting structure is an omni-directional reflector comprising a low-refractivity dielectric layer and a metal reflecting layer.
13. A light-emitting system comprising a plurality of LEDs, wherein each LED is formed using a method comprising:
forming a light-emitting epitaxial layer over a substrate; and
forming at least one V-shaped groove having a reflecting surface over the substrate;
wherein a vertical projection of a peripheral region of the light-emitting epitaxial layer margin is between a bottom and an inner side portion of the V-shaped groove such that light emitted from the light-emitting epitaxial layer margin is incident upon the reflecting surface of the V-shaped groove structure and reflected outwards,
the LED comprising:
the substrate having front and back main surfaces, and the at least one V-shaped groove having the reflecting surface formed over the front main surface of the substrate;
the light-emitting epitaxial layer over the substrate, wherein the peripheral region of the light-emitting epitaxial layer has the vertical projection between a bottom and an inner portion of the V-shaped groove, such that light emitted from the light-emitting epitaxial layer peripheral region is incident upon the reflecting surface of the V-shaped groove and reflected outwards.
14. The system of claim 13 , wherein an optical path of the light emitted from the peripheral region of the light-emitting epitaxial layer is adjusted by the V-shaped groove.
15. The system of claim 14 , wherein an angle between two side walls of the V-shaped groove is about 90 degrees such that light emitted at a vertical direction is reflected by the V-shaped groove and emits vertically after a parallel displacement outwards.
16. The system of claim 15 , wherein: the V-shaped groove has a depth of about 5-20 μm.
17. The system of claim 13 wherein an angle between two side walls of the V-shaped groove is an obtuse angle such that light emitted at a vertical direction is reflected by the V-shaped groove and emits outwards, thereby expanding a light emitting angle.
18. The system of claim 17 , wherein a reflecting structure is formed between the substrate and the light-emitting epitaxial layer, and wherein a vertical projection of the reflecting structure is at an inner side of the V-shaped groove.
19. The system of claim 18 , wherein the reflecting structure is an omni-directional reflector comprising a low-refractivity dielectric layer and a metal reflecting layer.