Light emitting device
View Patent ↗This disclosure discloses a light-emitting device. The light-emitting device comprise a light-emitting stack having a first-type semiconductor layer, a second-type semiconductor layer, and an active formed between the first-type semiconductor layer and the second-type semiconductor layer and emitting a light; and a reflective structure formed on the first-type semiconductor layer and having a first interface and a second interface; wherein the critical angle of the light at the first interface is larger than that at the second interface; and wherein the reflective structure ohmically contacts the first-type semiconductor layer at the first interface.
1. An light-emitting device, comprising:
a light-emitting stack having a first-type semiconductor layer, a second-type semiconductor layer, and an active layer formed between the first-type semiconductor layer and the second-type semiconductor layer and emitting a light; and
a reflective structure formed on the first-type semiconductor layer and having a first interface and a second interface, and the reflective structure comprises a transparent conductive layer, a void and a metal layer contacting the transparent conductive layer, wherein the first interface is formed between the transparent conductive layer and the first-type semiconductor layer, and an area of the first interface is more than an area of the second interface;
wherein a critical angle of the light at the first interface is larger than that at the second interface; and
wherein the reflective structure ohmically contacts the first-type semiconductor layer at the first interface; and
wherein the void is formed within the transparent conductive layer and devoid of contacting the metal layer.
2. The light-emitting device of claim 1 , wherein the second interface is formed between the void and the first-type semiconductor layer.
3. The light-emitting device of claim 1 , wherein the void contains air, N 2 , He, or Ar.
4. The light-emitting device of claim 1 , wherein the void has an elongated structure or a net structure.
5. The light-emitting device of claim 1 , wherein the void has a height smaller than 800 Å.
6. The light-emitting device of claim 1 , further comprising an electrode formed on the second-type semiconductor layer, wherein the electrode comprises an electrode pad and an extension electrode, and the void is at a position corresponding to the extension electrode.
7. The light-emitting device of claim 1 , wherein the void is surrounded by the transparent conductive layer and the first-type semiconductor layer.
8. The light-emitting device of claim 6 , wherein the void has a width larger than a width of the extension electrode.
9. The light-emitting device of claim 1 , wherein the transparent conductive layer comprises metal oxide.