Light emitting diode and fabrication method thereof
A light-emitting diode includes a light-emitting epitaxial layer having a first surface as a light-emitting surface and a second surface opposing the first surface, a first type semiconductor layer, an active layer, and a second type semiconductor layer; a transparent dielectric layer located on the second surface and in direct contact with the light-emitting epitaxial laminated layer, and having conductive through-holes therein; a transparent conductive layer located on one side surface of the transparent dielectric layer that is distal from the light-emitting epitaxial laminated layer; and a metal reflective layer located on one side surface of the transparent conductive layer that is distal from the transparent dielectric layer; wherein the transparent dielectric layer includes a first layer and a second layer; and wherein the first layer is thicker than the second layer, and a refractivity of the first layer is less than a refractivity of the second layer.
1. A light-emitting device (LED), comprising:
a light-emitting epitaxial layer having a first surface as a light-emitting surface and a second surface opposing the first surface, the light-emitting epitaxial layer including a first type semiconductor layer, an active layer, and a second type semiconductor layer;
a transparent dielectric layer located on the second surface and in direct contact with the light-emitting epitaxial laminated layer, and having conductive through-holes therein;
a transparent conductive layer located on one side surface of the transparent dielectric layer that is distal from the light-emitting epitaxial laminated layer; and
a metal reflective layer located on one side surface of the transparent conductive layer that is distal from the transparent dielectric layer;
wherein the transparent dielectric layer includes a first layer and a second layer; and
wherein the first layer is thicker than the second layer, and a refractivity of the first layer is less than a refractivity of the second layer.
2. The LED of claim 1 , further comprising a protective layer formed seamlessly on a surface of the metal reflective layer and on a side wall of the metal reflective layer.
3. The LED of claim 2 , wherein an angle between the side wall of the metal reflective layer and the second surface is 30°-85°.
4. The LED of claim 1 , wherein the transparent conductive layer has a thickness of 10-100 Å.
5. The LED of claim 1 , wherein a thickness of the transparent dielectric layer is more than 50 nm.
6. The LED of claim 1 , wherein the first surface of the light-emitting epitaxial laminated layer has a plurality of roughened patterns in a honeycomb structure, having a regular hexagon distribution.
7. The LED of claim 1 , wherein refractivities of the light-emitting epitaxial laminated layer, the first layer and the transparent conductive layer are r1, r2, and r3 respectively, with a relationship satisfying: r2<r3<r1.
8. The LED of claim 1 , wherein the first layer has a refractivity of less than 1.5.
9. The LED of claim 1 , wherein the transparent dielectric layer includes a silicon dioxide material layer, and wherein the conductive through-holes are filled with transparent conductive materials.
10. The LED of claim 1 , wherein the conductive through-holes are filled with a metal ohmic contact layer; and wherein the one side surface of the transparent dielectric layer that is distal from the light-emitting epitaxial laminated layer is flush with the first transparent conductive layer.
11. The LED of claim 1 , wherein the second layer has a thickness that is less than 1% of a thickness of the first layer.
12. The LED of claim 1 , wherein the first layer is composed of a plurality of sub-layers.
13. Alight-emitting device (LED), comprising:
a light-emitting epitaxial layer having a first surface as a light-emitting surface and a second surface opposing the first surface, including a first type semiconductor layer, an active layer, and a second type semiconductor layer;
a transparent dielectric layer located on the second surface of the light-emitting epitaxial laminated layer and in direct contact with the light-emitting epitaxial laminated layer, and having conductive through-holes therein;
a transparent conductive layer located on one side surface of the transparent dielectric layer that is distal from the light-emitting epitaxial laminated layer;
a metal reflective layer located on one side surface of the transparent conductive layer that is distal from the transparent dielectric layer;
wherein the transparent dielectric layer includes a laminated structure alternately stacked with a first sub-layer and a second sub-layer, and a refractivity of the first sub-layer is less than refractivity of the second sub-layer.
14. The LED of claim 13 , wherein the first sub-layer is thicker than the second sub-layer.
15. The LED of claim 13 , wherein refractivities of the light-emitting epitaxial laminated layer, the first sub-layer and the transparent conductive layer are r1, r2, and r3 respectively, with a relationship satisfying: r2<r3<r1.
16. The LED of claim 13 , wherein thicknesses the first sub-layer and the second sub-layer have a gradual distribution and decrease gradually from a maximum at the epitaxial laminated layer.
17. The LED of claim 13 , wherein the transparent dielectric layer further includes a third sub-layer formed on the laminated structure and distal from the light-emitting epitaxial layer.
18. The LED of claim 17 , wherein the third sub-layer is made of SiO 2 .
19. The LED of claim 13 , wherein the transparent dielectric layer includes a silicon dioxide material layer, and wherein the conductive holes are filled with transparent conductive materials.
20. The LED of claim 13 , further comprising a protective layer formed seamlessly on a surface of the metal reflective layer and on a side wall of the metal reflective layer, wherein an angle between the side wall of the metal reflective layer and the second surface is 30°-85°.