Light emitting device having light extraction structure and method for manufacturing the same
A light emitting device including a support layer; a reflective electrode disposed on the support layer; an ohmic electrode disposed on the reflective electrode, the ohmic electrode including a transparent electrode; and a semiconductor structure disposed on the ohmic electrode, the semiconductor structure including a p-type semiconductor layer disposed on the ohmic electrode; a light emitting layer disposed on the p-type semiconductor layer; and an n-type semiconductor layer disposed on the light emitting layer. Further, the transparent electrode has a thickness in the range of 40 nm to 90 nm.
1. A light emitting device, comprising:
a support layer;
a reflective electrode disposed on the support layer;
an ohmic electrode disposed on the reflective electrode, the ohmic electrode comprising a transparent electrode;
a semiconductor structure disposed on the ohmic electrode, the semiconductor structure comprising:
a p-type semiconductor layer disposed on the ohmic electrode;
a light emitting layer disposed on the p-type semiconductor layer; and
an n-type semiconductor layer disposed on the light emitting layer; and
a light extraction structure disposed in the n-type semiconductor layer,
wherein the transparent electrode has a thickness in the range of 40 nm to 90 nm,
wherein a distance between the reflective electrode and a center of the light emitting layer falls within the range represented by 0.65λ/n to 0.85λ/n, where “λ” represents a wavelength of light emitted from the light emitting layer and “n” represents a refractive index of the semiconductor structure, and
wherein the light extraction structure has an average periodicity of 0.8 μm to 5 μm.
2. The device of claim 1 , wherein the transparent electrode includes indium tin oxide (ITO), indium zinc oxide (IZO), aluminum zinc oxide (AZO), magnesium zinc oxide (MZO), or gallium zinc oxide (GZO).
3. The device of claim 1 , wherein a thickness of the p-type semiconductor layer is 100 nm.
4. The device of claim 1 , wherein the thickness of the transparent electrode is 70 nm.
5. The device of claim 1 , wherein the reflective electrode has a reflectance of 50% or more.
6. The device of claim 1 , further comprising an n-type electrode disposed on a portion of the n-type semiconductor layer.
7. The device of claim 6 , wherein the light extraction structure is not formed on a region wherein the n-type electrode is disposed.
8. The device of claim 1 , wherein the light extraction structure comprises holes or rods formed on the n-type semiconductor layer.
9. The device of claim 8 , wherein the light extraction structure has a periodicity of 1 μm or more.
10. The device of claim 8 , wherein the holes have a depth in the range of 300 nm to 3,000 nm, and the rods have a height in the range of 30 nm to 3,000 nm.
11. The device of claim 8 , wherein the holes or rods have a diameter in the range of 0.25a to 0.45a, where “a” represents an average periodicity of the light extraction structure.
12. The device of claim 1 , wherein the support layer comprises a semiconductor or a metal.
13. The device of claim 1 , wherein the light extraction structure comprises a material that is the same as the material of the semiconductor structure.
14. The device of claim 1 , wherein the light extraction structure is formed by etching the semiconductor structure.
15. The device of claim 1 , wherein a thickness of the p-type semiconductor layer corresponds to constructive interference condition between a light emitted from the light emitting layer and a light reflected by the reflective electrode.
16. The device of claim 1 , wherein the distance between the reflective electrode and the center of the light emitting layer falls within the range represented by 0.65λ/n to 0.76λ/n.
17. A package structure, comprising:
a body; and
the light emitting device of claim 1 disposed on the body.