Light emitting device having light extraction structure and method for manufacturing the same
View Patent ↗A light emitting device having a light extraction structure, which is capable of achieving an enhancement in light extraction efficiency and reliability, and a method for manufacturing the same. The light emitting device includes a semiconductor layer having a multi-layered structure including a light emission layer; and a light extraction structure formed on the semiconductor layer in a pattern having unit structures. Further, the wall of each of the unit structures is sloped at an angle of −45° to +45° from a virtual vertical line being parallel to a main light emitting direction of the light emitting device.
1. A light emitting device, comprising:
a semiconductor layer having a multi-layered structure including a light emission layer; and
a light extraction structure arranged on the semiconductor layer, the light extraction structure comprising a unit structure having at least one of a hole or a rod shape,
wherein the unit structure has a beveled wall and a truncated shape, and
wherein a slope of the beveled wall is configured such that an average filling factor of the light extraction structure is more than 5% and less than 37% with respect to a total area of a main light emission surface.
2. The light emitting device according to claim 1 , wherein a period of the light extraction structure or the average distance between the centers of the neighboring unit structures is 400˜3,000 nm.
3. The light emitting device according to claim 1 , wherein a height of the unit structures is λ/2n˜3,000 nm, n representing a refraction index of a material, on which the light extraction structure, and λ represents a central wavelength of the light emission layer.
4. The light emitting device according to claim 3 , wherein n represents a highest refraction index among refraction indexes of the light extraction layer or the semiconductor layer.
5. The light emitting device according to claim 1 , wherein the light extraction structure is formed on a light extraction layer located on the semiconductor layer.
6. The light emitting device according to claim 5 , wherein the light extraction structure is formed in the light extraction layer.
7. The light emitting device according to claim 5 , wherein the light extraction layer includes two or more sub-layers.
8. The light emitting device according to claim 5 , wherein a refraction index of the light extraction layer is different from a refraction index of the semiconductor layer.
9. The light emitting device according to claim 5 , wherein the light extraction layer comprises a dielectric material.
10. The light emitting device according to claim 1 , wherein the light extraction structure is formed in the semiconductor layer.
11. The light emitting device according to claim 1 , wherein the light extraction structure is a photonic crystal comprising one of a rectangular lattice, a triangular lattice, and an Archimedean lattice, or comprising one of a random structure, a Quasi-crystal structure, and a Quasi-random structure.
12. The light emitting device according to claim 1 , wherein the beveled wall of the unit structure is sloped at an angle of −45° to +45° (excluding 0°) from a virtual vertical line perpendicular to the main light emission surface.
13. The light emitting device according to claim 1 , wherein a material of the light extraction structure and a material of the semiconductor layer comprise a common material.
14. The light emitting device according to claim 1 , further comprising:
a support layer on the semiconductor layer, the support layer comprising a metal or a semiconductor.
15. The light emitting device according to claim 14 , further comprising:
an electrode between the semiconductor layer and the support layer.
16. A light emitting device, comprising:
a semiconductor layer having a multi-layered structure including a light emission layer;
a light extraction layer arranged on the semiconductor layer, the light extraction layer including a dielectric material; and
a light extraction structure arranged on the semiconductor layer, the light extraction structure including a unit structure having at least one of a hole or a rod shape,
wherein the unit structure has a beveled wall and a truncated shape, and
wherein a slope of the beveled wall is configured such that an average filling factor of the light extraction structure is more than 5% and less than 37% with respect to a total area of a main light emission surface.
17. The light emitting device according to claim 16 , wherein the beveled wall of the unit structure is sloped at an angle of −45° to +45° (excluding 0°)from a virtual vertical line perpendicular to the main light emission surface.
18. The light emitting device according to claim 16 , wherein a height of the unit structure is λ/2n˜3,000 nm, n representing a refraction index of a material of the light extraction structure, and 2 representing a central wavelength of the light emission layer.
19. The light emitting device according to claim 16 , wherein a period of the light extraction structure or an average distance between centers of neighboring unit structures is 400˜3,000 nm.
20. The light emitting device according to claim 16 , wherein a refraction index of the light extraction layer is different from a refraction index of the semiconductor layer.