Light-emitting device

1. A light-emitting device, comprising:

a light-emitting stack having an active layer;

a transparent insulating layer on the light-emitting stack;

an insulating layer under the light-emitting stack; and

an electrode structure having a first electrode on the transparent insulating layer;

wherein a surface area of a surface of the first electrode distal from the transparent insulating layer is smaller than a surface area of a surface of the transparent insulating layer distal from the light-emitting stack, the refractive index of the transparent insulating layer is between 1 and 3.4 both inclusive, and the transmittance of the transparent insulating layer is greater than 80%.

2. The light-emitting device according to claim 1 , wherein the transparent insulating layer comprises an edge and the first electrode comprises an edge, and a part of the edge of the transparent insulating layer protrudes relatively to the edge of the first electrode.

3. The light-emitting device according to claim 1 , wherein the transparent insulating layer has a thickness not less than 800 angstrom (Å).

4. The light-emitting device according to claim 1 , wherein the transparent insulating layer comprises oxide material.

5. The light-emitting device according to claim 4 , wherein the oxide material comprises aluminum zinc oxide.

6. The light-emitting device according to claim 1 , further comprising an electrical contact layer on the light-emitting stack and in contact with the transparent insulating layer.

7. The light-emitting device according to claim 1 , wherein the electrode structure further comprises an electrode and an extension electrode overlaying and in direct contact with a part of the electrical contact layer, and the transparent insulating layer separates the electrode from another part of the electrical contact layer.

8. The light-emitting device according to claim 1 , wherein a bottom surface of the transparent insulating layer and a bottom surface of the electrical contact layer are substantially coplanar on the light-emitting stack.

9. The light-emitting device according to claim 1 , further comprising a substrate under the insulating layer.

10. The light-emitting device according to claim 9 , further comprising a reflective layer between the substrate and the insulating layer.

11. The light-emitting device according to claim 1 , wherein the insulating layer has a refractive index less than 1.4.

12. The light-emitting device according to claim 1 , wherein the light-emitting stack comprises a window layer between the insulating layer and the active layer, wherein the window layer has a refractive index greater than that of the insulating layer.

13. The light-emitting device according to claim 1 , further comprising a transparent conductive layer overlaying a surface of the insulating layer.

14. The light-emitting device according to claim 1 , wherein the insulating layer comprises halide.

15. The light-emitting device according to claim 1 , wherein the insulating layer comprises IIA-VIIA compound.

16. A light-emitting device, comprising:

a light-emitting stack having an active layer;

a transparent insulating layer on the light-emitting stack; and

an electrode structure having a first electrode on the transparent insulating layer; wherein a surface area of a surface of the first electrode distal from the transparent insulating layer is smaller than a surface area of a surface of the transparent insulating layer distal from the light-emitting stack, the refractive index of the transparent insulating layer is between 1 and 3.4 both inclusive, the transmittance of the transparent insulating layer is greater than 80%, and the transparent insulating layer comprises oxide material.

17. The light-emitting device according to claim 16 , wherein the oxide material comprises aluminum zinc oxide.

18. The light-emitting device according to claim 16 , further comprises an electrical contact layer on the light-emitting stack and in contact with the transparent insulating layer.

19. The light-emitting device according to claim 18 , wherein the electrode structure further comprises an electrode and an extension electrode overlaying and in direct contact with a part of the electrical contact layer, and the transparent insulating layer separates the electrode from another part of the electrical contact layer.

20. The light-emitting device according to claim 18 , wherein a bottom surface of the transparent insulating layer and a bottom surface of the electrical contact layer are substantially coplanar on the light-emitting stack.