Light emitting element, method of manufacturing the same, and display device including the same
A light emitting element includes a first semiconductor layer including a first type of semiconductor, the first semiconductor layer including a 1-1-th semiconductor layer and a 1-2-th semiconductor layer, which are arranged in a length direction of the light emitting element; a second semiconductor layer including a second type of semiconductor different from the first type; an active layer disposed between the 1-2-th semiconductor layer and the second semiconductor layer; and an intermediate layer disposed between the 1-1-th semiconductor layer and the 1-2-th semiconductor layer and having a porous structure.
1. A light emitting element comprising:
a first semiconductor layer including a first type of semiconductor doped with a first conductivity type dopant, the first semiconductor layer including:
a 1-1-th semiconductor layer doped with the first conductivity type dopant; and
a 1-2-th semiconductor layer doped with the first conductivity type dopant, which are arranged in a length direction of the light emitting element;
a second semiconductor layer including a second type of semiconductor different from the first type;
an active layer disposed between the 1-2-th semiconductor layer and the second semiconductor layer; and
an intermediate layer disposed between the 1-1-th semiconductor layer and the 1-2-th semiconductor layer and having a porous structure; wherein
the first semiconductor layer, the second semiconductor layer, the active layer, and the intermediate layer each comprise a corresponding outer peripheral surface aligned in the length direction, and
the outer peripheral surfaces are vertically aligned forming the light emitting element in a columnar shape in the length direction.
2. The light emitting element of claim 1 , wherein the intermediate layer includes:
a first doped layer doped with the first conductivity type dopant having a first concentration; and
a second doped layer doped with the first conductivity type dopant having a second concentration less than the first concentration.
3. The light emitting element of claim 2 , wherein the first doped layer and the second doped layer are alternately arranged in the length direction.
4. The light emitting element of claim 1 , wherein the intermediate layer includes at least one of GaN, InGaN, and InN.
5. The light emitting element of claim 2 , wherein a thickness of the first doped layer is greater than a thickness of the second doped layer.
6. The light emitting element of claim 2 , wherein the first concentration is 10 times the second concentration or more.
7. The light emitting element of claim 2 , wherein
the first concentration is about 10 18 cm −3 or more, and
the second concentration is about 10 17 cm −3 or less.
8. The light emitting element of claim 2 , wherein
the first doped layer has a first thickness (T 1 ) that satisfies Equation 1, and
the second doped layer has a second thickness (T 2 ) that satisfies Equation 2, wherein
Equation 1 is defined as follows:
T
1
=
λ
m
4
n
1
wherein n 1 is a refractive index of the first doped layer, λ is a wavelength [nm] of light emitted from the active layer, m=2h 1 −1, and h 1 is an integer greater than or equal to 1, and
Equation 2 is defined as follows:
T
2
=
λ
m
4
n
2
wherein n 2 is a refractive index of the second doped layer, λ is the wavelength [nm] of the light emitted from the active layer, m=2h 2 −1, and h 2 is an integer greater than or equal to 1.
9. The light emitting element of claim 8 , wherein a thickness of the intermediate layer is in a range of about 1 μm to about 2 μm.
10. The light emitting element of claim 9 , wherein
the sum of thicknesses of the intermediate layer, the 1-1-th semiconductor layer, and the 1-2-th semiconductor layer is 3 μm or more.
11. The light emitting element of claim 1 , wherein the intermediate layer reflects light emitted from the active layer in a direction from the first semiconductor layer toward the second semiconductor layer.
12. The light emitting element of claim 1 , further comprising an insulating film completely surrounding the outer peripheral surfaces and extending in the length direction.
13. A display device comprising:
a substrate; and
a display element part including:
a light emitting element disposed on the substrate and emitting light;
a first contact electrode electrically connected to an end of the light emitting element; and
a second contact electrode electrically connected to another end of the light emitting element, wherein
the light emitting element includes:
a first semiconductor layer including a first type of semiconductor doped with a first conductivity type dopant, the first semiconductor layer including:
a 1-1-th semiconductor layer doped with the first conductivity type dopant; and
a 1-2-th semiconductor layer doped with the first conductivity type dopant, which are arranged in a length direction of the light emitting element;
a second semiconductor layer including a second type of semiconductor different from the first type;
an active layer disposed between the 1-2-th semiconductor layer and the second semiconductor layer; and
an intermediate layer disposed between the 1-1-th semiconductor layer and the 1-2-th semiconductor layer and having a porous structure; wherein
the first semiconductor layer, the second semiconductor layer, the active layer, and the intermediate layer each comprise a corresponding outer peripheral surface aligned in the length direction, and
the outer peripheral surfaces are vertically aligned forming the light emitting element in a columnar shape in the length direction.
14. The display device of claim 13 , wherein
the first contact electrode includes an opaque conductive material and is electrically connected to the 1-1-th semiconductor layer, and
the second contact electrode includes a transparent conductive material and is electrically connected to the 1-2-th semiconductor layer.
15. The display device of claim 14 , wherein the intermediate layer includes:
a first doped layer doped with the first conductivity type dopant having a first concentration; and
a second doped layer doped with the first conductivity type dopant having a second concentration less than the first concentration.
16. The light emitting element of claim 1 , wherein
the second semiconductor layer is doped with a second conductivity type dopant different from the first conductivity type dopant.
17. The light emitting element of claim 16 , wherein
the intermediate layer comprises first doped layers and second doped layers alternately arranged in the length direction;
the first doped layer and the second doped layer each including the first type of semiconductor doped with the first conductivity type dopant;
the first doped layer doped with the first conductivity type dopant having a first concentration; and
the second doped layer doped with the first conductivity type dopant having a second concentration less than the first concentration.