Light-emitting device and display apparatus including the same
A light-emitting device may include a light-emitting cell emitting first-color light and second-color light, an insulating layer having a flat upper surface while covering the light-emitting cell, a first trench exposing a first semiconductor layer, a second trench exposing a second semiconductor layer, a first electrode in contact with the first semiconductor layer, a second electrode in contact with the second semiconductor layer, and a third electrode in contact with a third semiconductor layer.
1. A light-emitting device comprising:
a light-emitting cell comprising a first semiconductor layer, a first active layer emitting first-color light, a second semiconductor layer, a second active layer emitting second-color light, and a third semiconductor layer, wherein the first semiconductor layer is provided on the first active layer, the first active layer is provided on the second semiconductor layer, the second semiconductor layer is provided on the second active layer, and the second active layer is provided on the third semiconductor layer;
an insulating layer provided on the light-emitting cell, the insulating layer having a flat upper surface;
a first trench exposing the first semiconductor layer by penetrating through the insulating layer;
a second trench exposing the second semiconductor layer by penetrating through the insulating layer;
a first electrode extending from the first semiconductor layer to an upper surface of the insulating layer along the first trench;
a second electrode extending from the second semiconductor layer to the upper surface of the insulating layer along the second trench; and
a third electrode provided to be in contact with the third semiconductor layer,
wherein a thickness of a first portion of the insulating layer adjacent to the first electrode is different than a thickness of a second portion of the insulating layer adjacent the second electrode.
2. The light-emitting device of claim 1 ,
wherein the insulating layer comprises:
a first insulating layer provided on an upper surface of the light-emitting cell, side surfaces of the first trench, and side surfaces of the second trench; and
a second insulating layer arranged on an upper surface the first insulating layer and configured to reduce a difference between a height of a portion of the first electrode extending outside of the first trench and a portion of the second electrode extending outside of the second trench.
3. The light-emitting device of claim 2 ,
wherein a first height of the first electrode from a lower surface of the light-emitting device and a second height of the second electrode from the lower surface of the light-emitting device are substantially equal, or within 10% of a thickness of the light-emitting device.
4. The light-emitting device of claim 1 , further comprising a third trench exposing the third semiconductor layer by penetrating the insulating layer and a partial area of the light-emitting cell,
wherein the third electrode extends from the third semiconductor layer to the upper surface of the insulating layer along the third trench.
5. The light-emitting device of claim 4 ,
wherein the first active layer is configured to emit the first-color light,
wherein the second active layer is configured to emit the second-color light, and
wherein only the first active layer or the second active layer is arranged in a partial area of the light-emitting cell viewed from a top view.
6. The light-emitting device of claim 4 ,
wherein the first semiconductor layer and the third semiconductor layer have a same polarity, and the second semiconductor layer has a polarity different from the polarity of the first semiconductor layer,
the first electrode and the third electrode have a same polarity, and the second electrode has a polarity opposite to the polarity of the first electrode.
7. The light-emitting device of claim 4 ,
wherein the light-emitting cell is configured to emit the first-color light as the second electrode is connected to the first electrode, and
the light-emitting cell is configured to emit the second-color light as the second electrode is connected to the third electrode.
8. The light-emitting device of claim 4 ,
wherein the second semiconductor layer comprises a first sub-semiconductor layer and a second sub-semiconductor layer,
the second trench comprises a first sub-trench and a second sub-trench spaced apart from the first sub-trench,
the first sub-trench exposes the first sub-semiconductor layer by penetrating through the insulating layer,
the second sub-trench exposes the second sub-semiconductor layer by penetrating through the insulating layer and a partial area of the light-emitting cell,
the second electrode comprises a first sub-electrode and a second sub-electrode spaced apart from the first sub-electrode,
the first sub-electrode extends from the first sub-semiconductor layer to the upper surface of the insulating layer along the first sub-trench, and
the second sub-electrode extends from the second sub-semiconductor layer to the upper surface of the insulating layer along the second sub-trench.
9. The light-emitting device of claim 8 ,
wherein the second sub-semiconductor layer has a greater width than a width of the first sub-semiconductor layer.
10. The light-emitting device of claim 8 ,
wherein the first electrode is electrically connected to the first sub-electrode, and the first active layer is configured to emit the first-color light, and
the third electrode is electrically connected to the second sub-electrode, and the second active layer is configured to emit the second-color light.
11. The light-emitting device of claim 8 ,
wherein a position of the first electrode or a position of the first sub-electrode of the light-emitting device arranged in a first direction does not overlap a position of the second electrode or a position of the second sub-electrode of the light-emitting device arranged in a second direction rotated by 180 degrees in the first direction.
12. The light-emitting device of claim 1 ,
wherein the light-emitting cell comprises a first-color light-emitting structure and a second-color light-emitting structure,
the second semiconductor layer is comprised in common in the first-color light-emitting structure and the second-color light-emitting structure, and
no bonding layer is between the first-color light-emitting structure and the second-color light-emitting structure.
13. The light-emitting device of claim 1 , further comprising a distributed Bragg reflector (DBR) layer between the first active layer and the second active layer,
wherein, in the DBR layer, a reflectance of the first-color light is greater than a transmittance of the first-color light, and a transmittance of the second-color light is greater than a reflectance of the second-color light.
14. The light-emitting device of claim 1 ,
wherein the third electrode is provided on a lower surface of the light-emitting cell,
wherein the second electrode is electrically connected to the first electrode, and wherein the first active layer is configured to emit the first-color light,
the second electrode is electrically connected to the third electrode, and the second active layer is configured to emit the second-color light.
15. The light-emitting device of claim 1 ,
wherein the light-emitting cell further comprises a third active layer emitting third-color light, and
the first-color light, the second-color light, and the third-color light configure one pixel.
16. The light-emitting device of claim 1 ,
wherein the second electrode is arranged at a center of the light-emitting device, and
the first electrode is symmetrical with respect to the center of the light-emitting device.
17. The light-emitting device of claim 1 ,
wherein a planar shape of the light-emitting device is rotationally symmetric with respect to at least one angle.
18. The light-emitting device of claim 1 ,
wherein the light-emitting device has a circular, elliptical, or polygonal plane.
19. A display apparatus comprising:
an emission layer comprising a first-type light-emitting device according to claim 1 , the first-type light-emitting device having a first planar shape and configured to emit a plurality of colors of light;
a second-type light-emitting device having a second planar shape different from the first planar shape of the first-type light-emitting device and configured to emit a different color of light from the plurality of colors of light; and
a driving layer comprising a substrate and a plurality of transistors, wherein the substrate comprises a plurality of wells,
wherein the plurality of wells comprise a first well and a second well, which are adjacent to each other,
the first-type light-emitting device is exclusively arranged in the first well,
the second-type light-emitting device is exclusively arranged in the second well, and
the first well and the second well configure one pixel.
20. The display apparatus of claim 19 ,
wherein the first well has a first depth,
the first depth is a depth such that a height of each the first electrode, the second electrode and the third electrode from the lower surface of the light-emitting device substantially same or within 10% of a thickness of the first-type light-emitting device,
the second well has a second depth,
the second depth is a depth such that at least one electrode comprised in the second-type light-emitting device arranged in the second well is substantially at the height, or is a depth such that the at least one electrode has a height difference within 10% of a thickness of the first-type light-emitting device with the height.
21. The light-emitting device of claim 1 ,
wherein the insulating layer comprises:
a first insulating layer provided on an upper surface of the light-emitting cell; and
a second insulating layer provided on an upper surface the first insulating layer,
wherein a thickness of a first portion of the second insulating layer adjacent the first electrode is different than a thickness of a second portion of the second insulating layer adjacent the second electrode.
22. The light-emitting device of claim 1 ,
wherein an upper surface of the first semiconductor layer contacts a lower surface of the first portion of the insulating layer, and
wherein an upper surface of the second semiconductor layer contacts a lower surface of the second portion of the insulating layer.
23. The light-emitting device of claim 1 ,
wherein the thickness of the first portion of the insulating layer is smaller than the thickness of the second portion of the insulating layer.