Light emitting device and light emitting device package
Provided are a light emitting device and a light emitting device package. The light emitting device includes a transparent substrate, a light emitting structure, and a first reflection layer. The light emitting structure includes a first conductive type semiconductor layer, an active layer, and a second conductive type semiconductor layer that are disposed on a top surface of the substrate. The first reflection layer is disposed on a bottom surface of the substrate. The bottom surface of the substrate has a surface roughness of about 1 nm to about 15 nm in root mean square (RMS) value.
1. A light emitting device comprising:
a conductive support member;
a reflection layer provided on the conductive support member;
an ohmic contact layer provided on the reflection layer and having a bottom surface, wherein the ohmic contact layer has a thickness of substantially 80 nm to 120 nm;
a light emitting structure comprising a first conductive type semiconductor layer, an active layer, and a second conductive type semiconductor layer that are coupled to the ohmic contact layer; and
an electrode provided on the first conductive type semiconductor layer, wherein the bottom surface of the ohmic contact layer has a surface roughness corresponding to a root mean square (RMS) value substantially in a range from 1 nm to 3 nm and wherein at least one part of an upper surface of the ohmic contact layer is in direct contact with the second conductive type semiconductor layer.
2. The light emitting device according to claim 1 , wherein the reflection layer comprises aluminum (Al) or silver (Ag).
3. The light emitting device according to claim 1 , wherein the light emitting structure emits light having a wavelength substantially in a range from 400 nm to 650 nm, and the reflection layer has a reflectance of about 75% or higher.
4. The light emitting device according to claim 1 , wherein the root mean square (RMS) value of the ohmic contact layer increases or decreases relative to the thickness of the ohmic contact layer.
5. The light emitting device according to claim 1 , wherein the light emitting structure emits light having a wavelength substantially in a range from 500 nm to 650 nm, and the reflection layer has a reflectance of about 80% or higher.
6. A light emitting device comprising:
a conductive support member;
a reflection layer provided on the conductive support member;
an ohmic contact layer provided on the reflection layer and having a bottom surface, wherein the ohmic contact layer has a thickness of substantially 180 nm to 220 nm;
a light emitting structure comprising a first conductive type semiconductor layer, an active layer, and a second conductive type semiconductor layer that are coupled to the ohmic contact layer; and
an electrode provided on the first conductive type semiconductor layer,
wherein the bottom surface of the ohmic contact layer has a surface roughness corresponding to a root mean square (RMS) value substantially in a range from 3 nm to 5 nm and wherein at least one part of an upper surface of the ohmic contact layer is in direct contact with the second conductive type semiconductor layer.
7. The light emitting device according to claim 6 , wherein the reflection layer comprises aluminum (Al).
8. The light emitting device according to claim 6 , wherein the light emitting structure emits light having a wavelength substantially in a range from 400 nm to 650 nm, and the reflection layer has a reflectance of about 75% or higher.
9. The light emitting device according to claim 6 , wherein the reflection layer comprises silver (Ag).
10. The light emitting device according to claim 6 , wherein the light emitting structure emits light having a wavelength substantially in a range from 530 nm to 650 nm, and the reflection layer has a reflectance of about 80% or higher.
11. The light emitting device of claim 6 , wherein the reflection layer is between the ohmic contact layer and the upper surface of the conductive support member.
12. A light emitting device comprising:
a support member;
a first layer having metal material provided on the support member;
a second layer having metal material provided on the first layer;
a light emitting structure comprising a first conductive type semiconductor layer, an active layer, and a second conductive type semiconductor layer; and
an electrode provided on the light emitting structure, wherein the second layer has a surface roughness corresponding to a root mean square (RMS) value substantially in a range from 1 nm to 5 nm,
wherein at least one part of the second layer is in contact with the light emitting structure, and
wherein the second layer has a thickness of substantially 80 nm to 120 nm or 180 nm to 220 nm.
13. The light emitting device according to claim 12 , wherein the first layer comprises aluminum (Al) or silver (Ag).
14. The light emitting device according to claim 12 , wherein the light emitting structure emits light having a wavelength substantially in a range from 400 nm to 650 nm, the surface roughness of the second layer is substantially in the range from 1 nm to 3 nm in RMS value and wherein the second layer has the thickness of substantially 80 nm to 120 nm.
15. The light emitting device according to claim 12 , wherein the light emitting structure emits light having a wavelength substantially in a range from 500 nm to 650 nm, the surface roughness of the second layer is substantially in the range from 1 nm to 3 nm in RMS value and the second layer has the thickness of substantially 80 nm to 120 nm.
16. The light emitting device according to claim 12 , wherein the light emitting structure emits light having a wavelength substantially in a range from 400 nm to 650 nm, the surface roughness of the second layer is substantially in the range from 3 nm to 5 nm in RMS value and the second layer has the thickness of substantially 180 nm to 220 nm.
17. The light emitting device according to claim 12 , wherein the light emitting structure emits light having a wavelength substantially in a range from 530 nm to 650 nm, the surface roughness of the second layer is substantially in the range from 3 nm to 5 nm in RMS value and the second layer has the thickness of substantially 180 nm to 220 nm.
18. The light emitting device according to claim 12 , wherein the first layer has a reflective material with a reflectance of about 80% or higher and the second layer has the thickness of substantially 80 nm to 120 nm.
19. The light emitting device according to claim 12 , wherein the first layer has a reflective material with a reflectance of about 75% or higher and the second layer has the thickness of substantially 180 nm to 220 nm.
20. The light emitting device according to claim 12 , wherein the second layer has a ohmic contact layer.