Light emitting device
A light emitting device includes a stacked structure and a first insulating layer covering at least side surfaces of the stacked structure including a p-type and n-type semiconductor layers, a light emitting layer sandwiched between the p-type and n-type semiconductor layers, an n-type electrode on the n-type semiconductor layer, an n-type contact layer sandwiched between the n-type semiconductor layer and the n-type electrode, a p-type electrode on the p-type semiconductor layer, an n-type contact pad on the n-type electrode, a p-type contact pad on the p-type electrode, and a semiconductor reflector between the light emitting layer and the n-type contact layer including multiple periods, each period including at least a first layer and at least a second layer having a refractive index different from a refractive index of the first layer. The light emitting device could be applied to wide color gamut (WCG) backlight modules or ultra-thin backlight modules.
1. A light emitting device, comprising:
a stacked structure comprising:
a p-type semiconductor layer;
an n-type semiconductor layer on the p-type semiconductor layer;
a light emitting layer sandwiched between the p-type semiconductor layer and the n-type semiconductor layer;
an n-type electrode on the n-type semiconductor layer;
an n-type contact layer sandwiched between the n-type semiconductor layer and the n-type electrode;
a p-type electrode on the p-type semiconductor layer;
an n-type contact pad on the n-type electrode;
a p-type contact pad on the p-type electrode; and
a semiconductor reflector between the light emitting layer and the n-type contact layer, the semiconductor reflector including multiple periods, each period comprising at least a first layer and at least a second layer, a refractive index of the first layer being different from a refractive index of the second layer; and
a first insulating layer covering at least side surfaces of the stacked structure.
2. The light emitting device of claim 1 , wherein the p-type semiconductor layer has a top surface facing away from the semiconductor reflector and the top surface is a rough surface.
3. The light emitting device of claim 1 , wherein the first insulating layer has a refractive index less than a refractive index of the p-type semiconductor layer.
4. The light emitting device of claim 1 , wherein the first insulating layer extends to a top surface of the p-type semiconductor layer.
5. The light emitting device of claim 1 , wherein the first insulating layer covers a bottom surface of the stacked structure and exposes a bottom part of the n-type contact pad and a bottom part of the p-type contact pad.
6. The light emitting device of claim 1 , wherein the n-type semiconductor layer has a first portion and a second portion spaced apart from the first portion by the semiconductor reflector.
7. The light emitting device of claim 2 , wherein the first insulating layer extends to cover the rough surface.
8. The light emitting device of claim 7 , wherein a top surface of the first insulating layer facing away from the p-type semiconductor layer has a similar shape with that of the rough surface.
9. The light emitting device of claim 1 , wherein the first layer and the second layer of the semiconductor reflector include aluminum, and an atomic percentage of the aluminum in the first layer is substantially different from an atomic percentage of the aluminum in the second layer.
10. The light emitting device of claim 1 , wherein the first layer of the semiconductor reflector includes Al x Ga 1-x As, wherein 0<x<1.
11. The light emitting device of claim 1 , wherein the second layer of the semiconductor reflector includes Al y Ga 1-y As, wherein 0<y<1.
12. The light emitting device of claim 1 , further comprising a second insulating layer covering the first insulating layer, wherein the second insulating layer has a refractive index different from a refractive index of the first insulating layer.
13. The light emitting device of claim 12 , wherein the refractive index of the second insulating layer is less than the refractive index of the first insulating layer.
14. The light emitting device of claim 4 , further comprising a second insulating layer covering the first insulating layer, wherein the second insulating layer has a refractive index different from a refractive index of the first insulating layer.
15. The light emitting device of claim 14 , wherein the refractive index of the second insulating layer is less than the refractive index of the first insulating layer.
16. The light emitting device of claim 7 , further comprising a second insulating layer covering the first insulating layer, wherein a refractive index of the second insulating layer is different from a refractive index of the first insulating layer.
17. The light emitting device of claim 16 , wherein the refractive index of the second insulating layer is less than the refractive index of the first insulating layer.
18. The light emitting device of claim 8 , further comprising a second insulating layer covering the first insulating layer, wherein a refractive index of the second insulating layer is different from a refractive index of the first insulating layer.
19. The light emitting device of claim 18 , wherein the refractive index of the second insulating layer is less than the refractive index of the first insulating layer.
20. The light emitting device of claim 18 , wherein a top surface of the second insulating layer facing away from the p-type semiconductor layer has a similar shape with that of the top surface of the first insulating layer.