Light emitting stacked structure and display device having the same
A light emitting stacked structure including a plurality of epitaxial sub-units disposed one over another, each of the epitaxial sub-units configured to emit different colored light, in which each epitaxial sub-unit has a light emitting area that overlaps one another, and at least one epitaxial sub-unit has an area different from the area of another epitaxial sub-unit.
1. A light emitting stacked structure comprising:
a substrate;
a plurality of epitaxial sub-units disposed on the substrate to define a first overlapping area between the substrate and the epitaxial sub-units, the epitaxial sub-units being disposed one over another to define a second overlapping area between adjacent epitaxial sub-units, each of the epitaxial sub-units configured to emit different colored light;
a first insulation layer disposed in the first overlapping area between the substrate and the epitaxial sub-units;
a second insulation layer disposed in the second overlapping area between adjacent epitaxial sub-units; and
a third insulation layer having a different thickness than that of the first and second insulation layers and covering opposing ends of each of the first insulation layer and the second insulation layer,
wherein:
each epitaxial sub-unit has a light emitting area that overlaps one another; and
at least one epitaxial sub-unit has an area different from the area of another epitaxial sub-unit.
2. The light emitting stacked structure of claim 1 , wherein the area of each epitaxial sub-unit decreases along a first direction.
3. The light emitting stacked structure of claim 2 , wherein, between two adjacent epitaxial sub-units, an upper epitaxial sub-unit completely overlaps a lower epitaxial sub-unit having a larger area.
4. The light emitting stacked structure of claim 1 , wherein light emitted from each epitaxial sub-unit has different energy bands from each other, and the energy bands increases along a first direction.
5. The light emitting stacked structure of claim 1 , wherein the epitaxial sub-units are independently drivable.
6. The light emitting stacked structure of claim 1 , wherein light emitted from a lower epitaxial sub-unit is configured to be emitted to the outside of the light emitting stacked structure by passing through an upper epitaxial sub-unit disposed on the lower epitaxial sub-unit.
7. The light emitting stacked structure of claim 6 , wherein the upper epitaxial sub-unit is configured to transmit at least about 80% of light emitted from the lower epitaxial sub-unit.
8. The light emitting stacked structure of claim 1 , wherein the epitaxial sub-units comprise:
a first epitaxial stack configured to emit a first color light;
a second epitaxial stack disposed on the first epitaxial stack and configured to emit a second color light having a wavelength band different from the first color light; and
a third epitaxial stack disposed on the second epitaxial stack and configured to emit a third color light having a wavelength band different from the first and second color lights.
9. The light emitting stacked structure of claim 8 , wherein the first, second, and third color lights are a red light, a green light, and a blue light, respectively.
10. The light emitting stacked structure of claim 8 , wherein each of the first, second, and third epitaxial stacks comprises:
a p-type semiconductor layer;
an active layer disposed on the p-type semiconductor layer; and
an n-type semiconductor layer disposed on the active layer.
11. The light emitting stacked structure of claim 10 , further comprising first, second, and third p-type contact electrodes connected to the p-type semiconductor layers of the first, second, and third epitaxial stacks, respectively,
wherein at least one of the epitaxial sub-units includes a through-hole penetrating through the at least one of the epitaxial sub-units, the second and third p-type contact electrodes being disposed in respective ones of the through-holes.
12. The light emitting stacked structure of claim 11 , wherein the first p-type contact electrode is disposed between the substrate and the first epitaxial stack.
13. The light emitting stacked structure of claim 11 , further comprising first, second, and third n-type contact electrodes connected to the n-type semiconductor layers of the first, second, and third epitaxial stacks, respectively.
14. The light emitting stacked structure of claim 13 , further comprising:
a common line applying a common voltage to the first, second, and third p-type contact electrodes; and
first, second, and third light emitting signal lines applying a light emitting signal to the first, second, and third n-type contact electrodes, respectively.
15. The light emitting stacked structure of claim 10 , wherein at least one of the semiconductor layers of the first, second, and third epitaxial stacks has a concave-convex pattern formed on one surface thereof.
16. The light emitting stacked structure of claim 8 , further comprising at least one of a first wavelength pass filter disposed between the first epitaxial stack and the second epitaxial stack, and a second wavelength pass filter disposed between the second epitaxial stack and the third epitaxial stack.
17. The light emitting stacked structure of claim 1 , wherein at least one of epitaxial sub-units comprises a micro LED having a surface area less than about 10,000 square μm.
18. A display device comprising:
a substrate;
a plurality of pixels, at least one of the pixels having a light emitting stacked structure including:
a plurality of epitaxial sub-units disposed on the substrate to define a first overlapping area between the substrate and the epitaxial sub-units, the epitaxial sub-units being disposed one over another to define a second overlapping area between adjacent epitaxial sub-units, each of the epitaxial sub-units configured to emit different colored light;
a first insulation layer disposed in the first overlapping area between the substrate and the epitaxial sub-units;
a second insulation layer disposed in the second overlapping area between adjacent epitaxial sub-units; and
a third insulation layer having a different thickness than that of the first and second insulation layers and covering opposing ends of each of the first insulation layer and the second insulation layer,
wherein:
each epitaxial sub-unit has a light emitting area that overlaps one another; and
at least one epitaxial sub-unit has an area different from the area of another epitaxial sub-unit.
19. The display device of claim 18 , wherein the display device is configured to be driven in a passive matrix manner.
20. The display device of claim 18 , wherein the display device is configured to be driven in an active matrix manner.