Light-emitting element, method of manufacturing light-emitting element, and display device including light-emitting element
A light-emitting element includes a first end portion and a second end portion disposed in a length direction of the light-emitting element, a first electrode corresponding to the first end portion, a first semiconductor layer on the first electrode, an active layer on the first semiconductor layer, a second semiconductor layer on the active layer, and a second electrode on the second semiconductor layer and corresponding to the second end portion. The second electrode includes a first layer on the first semiconductor layer, and a second layer on the first layer. The first semiconductor layer includes a p-type semiconductor layer doped with a p-type dopant. The second semiconductor layer includes an n-type semiconductor layer doped with an n-type dopant. The first electrode is in ohmic contact with the first semiconductor layer. The second electrode is in ohmic contact with the second semiconductor layer.
1. A method of manufacturing a light-emitting element, the method comprising:
providing a first substrate;
forming a light-emitting stack including a first electrode, a first semiconductor layer, an active layer, a second semiconductor layer, and a second electrode stacked on a first surface of the first substrate;
forming a buffer layer on the second electrode;
forming an adhesive layer on the buffer layer and arranging a second substrate on the adhesive layer to bond the first substrate and the second substrate;
turning the first substrate such that a second surface of the first substrate faces upward, the first surface and the second surface of the first substrate being opposite to each other;
removing the first substrate using a laser lift-off method to expose the first electrode;
etching the light-emitting stack in a vertical direction to form a light-emitting stack pattern and exposing a region of the buffer layer;
forming an insulating material layer on a surface of the light-emitting stack pattern and on the region of the buffer layer;
etching the insulating material layer in the vertical direction to form an insulating film surrounding the surface of the light-emitting stack pattern; and
separating the light-emitting stack pattern surrounded by the insulating film from the second substrate using a chemical lift-off method to form at least one light-emitting element, wherein
the at least one light-emitting element includes the second electrode, the second semiconductor layer, the active layer, the first semiconductor layer, and the first electrode disposed in a length direction of the at least one light-emitting element,
the first semiconductor layer includes an n-type semiconductor layer doped with an n-type dopant, and
the second semiconductor layer includes a p-type semiconductor layer doped with a p-type dopant.
2. The method of claim 1 , wherein
the first electrode is in ohmic contact with the first semiconductor layer, and
the second electrode is in ohmic contact with the second semiconductor layer.
3. The method of claim 2 , wherein
the at least one light-emitting element includes a first end portion and a second end portion that are disposed in the length direction,
the second electrode is disposed at the first end portion, and
the first electrode is disposed at the second end portion.
4. The method of claim 3 , wherein
the first electrode includes a first layer disposed on the first semiconductor layer, and a second layer disposed on the first layer, and
the first layer and the second layer include a transparent conductive material.
5. The method of claim 4 , wherein
the first layer includes a transparent metal, and
the second layer includes a transparent conductive oxide.
6. The method of claim 1 , wherein a thickness of a region of the insulating film corresponding to an outer circumferential surface of the first electrode gradually decreases upward in the length direction.
7. The method of claim 1 , wherein the buffer layer is an inorganic insulating film including an inorganic material.
8. The method of claim 1 , wherein the forming of the light-emitting stack includes:
forming the first electrode on the first substrate;
forming the first semiconductor layer on the first electrode;
forming the active layer on the first semiconductor layer;
forming the second semiconductor layer on the active layer; and
forming the second electrode on the second semiconductor layer.
9. The method of claim 1 , wherein the forming of the light-emitting stack pattern includes:
forming a mask on the exposed first electrode;
forming at least one fine pattern on the mask;
etching the mask to form at least one mask pattern corresponding to the at least one fine pattern;
vertically etching the remaining region excluding one region corresponding to the at least one mask pattern to form a groove; and
removing the at least one mask pattern.
10. The method of claim 1 , wherein a lower surface of the first electrode is substantially flat and parallel to an upper surface of the second electrode in the length direction.