Three dimensionally structured semiconductor light emitting diode and display apparatus
A three-dimensionally structured semiconductor light emitting diode includes a first conductivity-type semiconductor rod having integral first and second portions, the first portion defining a first surface, the second portion defining a second surface opposite the first surface, and a side surface between the first and second surfaces, an active layer and a second conductivity-type semiconductor layer on the side surface of the first conductivity-type semiconductor rod, the active layer and the second conductivity-type semiconductor layer being on the second portion of the first conductivity-type semiconductor rod, an insulating cap layer on the second surface of the first conductivity-type semiconductor rod, a transparent electrode layer on the second conductivity-type semiconductor layer, and a passivation layer on the transparent electrode layer and exposing a portion of the transparent electrode layer, the passivation layer extending to cover ends of the active layer and the second conductivity-type semiconductor layer adjacent to the first surface.
1. A three-dimensionally structured semiconductor light emitting diode, comprising:
a first conductivity-type semiconductor rod having first and second portions integral with each other, the first portion defining a first surface, the second portion defining a second surface opposite the first surface, and a side surface extending between the first surface and the second surface;
an active layer and a second conductivity-type semiconductor layer sequentially disposed on the side surface of the first conductivity-type semiconductor rod, the active layer and the second conductivity-type semiconductor layer being on the second portion of the first conductivity-type semiconductor rod;
an insulating cap layer on the second surface of the first conductivity-type semiconductor rod;
a transparent electrode layer on the second conductivity-type semiconductor layer; and
a passivation layer on the transparent electrode layer and exposing a portion of the transparent electrode layer, the passivation layer extending to cover a first end of the active layer and a first end of the second conductivity-type semiconductor layer adjacent to the first surface,
wherein the first conductivity-type semiconductor rod includes a regrowth layer on the side surface, the regrowth layer being on the second portion of the first conductivity-type semiconductor rod, and a combined structure of the regrowth layer with the first conductivity-type semiconductor rod having a hexagonal columnar shape, and
wherein the insulating cap layer overhangs the side surface of the first conductivity-type semiconductor rod.
2. The three-dimensionally structured semiconductor light emitting diode as claimed in claim 1 , wherein the first portion of the first conductivity-type semiconductor rod has a width smaller than a width of the second portion.
3. The three-dimensionally structured semiconductor light emitting diode as claimed in claim 1 , wherein the active layer has a second end coplanar with the second surface of the first conductivity-type semiconductor rod, the insulating cap layer covering and being in direct contact with the second end of the active layer.
4. The three-dimensionally structured semiconductor light emitting diode as claimed in claim 3 , wherein the second conductivity-type semiconductor layer has a second end coplanar with the second surface of the first conductivity-type semiconductor rod, the insulating cap layer extending to the second end of the second conductivity-type semiconductor layer, and the transparent electrode layer being in direct contact with the second end of the second conductivity-type semiconductor layer and with the insulating cap layer.
5. The three-dimensionally structured semiconductor light emitting diode as claimed in claim 4 , wherein the passivation layer includes a first insulating film on the second conductivity-type semiconductor layer, and a second insulating film on the first insulating film, the second insulating film extending to cover the first ends of the active layer and the second conductivity-type semiconductor layer adjacent to the first surface.
6. The three-dimensionally structured semiconductor light emitting diode as claimed in claim 1 , wherein the passivation layer extends to a lateral surface of the first portion of the first conductivity-type semiconductor rod.
7. The three-dimensionally structured semiconductor light emitting diode as claimed in claim 1 , wherein the exposed portion of the transparent electrode layer overlaps the insulating cap layer.
8. The three-dimensionally structured semiconductor light emitting diode as claimed in claim 1 , wherein the exposed portion of the transparent electrode layer is on the side surface of the first conductivity-type semiconductor rod adjacent to the second surface.
9. The three-dimensionally structured semiconductor light emitting diode as claimed in claim 1 , further comprising:
a first connection electrode connected to the first surface of the first conductivity-type semiconductor rod; and
a second connection electrode connected to a portion of the transparent electrode layer on the insulating cap layer.
10. The three-dimensionally structured semiconductor light emitting diode as claimed in claim 9 , wherein the first connection electrode extends to a lateral surface of the first portion of the first conductivity-type semiconductor rod.
11. The three-dimensionally structured semiconductor light emitting diode as claimed in claim 1 , wherein the first surface of the first conductivity-type semiconductor rod includes a cleavage plane of a first conductivity-type semiconductor.
12. The three-dimensionally structured semiconductor light emitting diode as claimed in claim 1 , wherein the first conductivity-type semiconductor rod, the active layer, and the second conductivity-type semiconductor layer include nitride semiconductor single crystal.
13. The three-dimensionally structured semiconductor light emitting diode as claimed in claim 1 , wherein an aspect ratio of the first conductivity-type semiconductor rod is equal to or greater than 4.
14. A three-dimensionally structured semiconductor light emitting diode, comprising:
a first conductivity-type semiconductor rod having first and second portions integral with each other, the first portion defining a first surface, the second portion defining a second surface opposite the first surface, and a side surface extending between the first surface and the second surface;
an active layer and a second conductivity-type semiconductor layer sequentially disposed on a lateral surface of the second portion of the first conductivity-type semiconductor rod;
an insulating cap layer on the second surface of the first conductivity-type semiconductor rod;
a transparent electrode layer on the insulating cap layer and on the second conductivity-type semiconductor layer; and
a passivation layer on the transparent electrode layer, the passivation layer exposing a portion of the transparent electrode layer on the insulating cap layer,
wherein the first conductivity-type semiconductor rod includes a regrowth layer on the side surface, the regrowth layer being on the second portion of the first conductivity-type semiconductor rod, and a combined structure of the regrowth layer with the first conductivity-type semiconductor rod having a hexagonal columnar shape, and
wherein the insulating cap layer overhangs the side surface of the first conductivity-type semiconductor rod.
15. The three-dimensionally structured semiconductor light emitting diode as claimed in claim 14 , wherein the passivation layer covers a first end of the active layer and a first end of the second conductivity-type semiconductor layer adjacent to the first surface.
16. The three-dimensionally structured semiconductor light emitting diode as claimed in claim 14 , further comprising:
a first connection electrode connected to the first surface of the first conductivity-type semiconductor rod, the first connection electrode extending to a lateral surface of the first portion adjacent to the first surface; and
a second connection electrode connected to a first portion of the transparent electrode layer on the insulating cap layer, the second connection electrode extending to a second portion of the transparent electrode layer adjacent to the second surface.
17. The three-dimensionally structured semiconductor light emitting diode as claimed in claim 14 , wherein a length of the first portion of the first conductivity-type semiconductor rod is within a range of about 20% to about 50% of a total length of the first conductivity-type semiconductor rod.
18. A display device, comprising:
a plurality of pixels;
a first electrode portion and a second electrode portion in each of the plurality of pixels, the first and second electrode portions being spaced apart from each other; and
a three-dimensionally structured semiconductor light emitting diode between the first electrode portion and the second electrode portion in each of the plurality of pixels, the three-dimensionally structured semiconductor light emitting diode including:
a first conductivity-type semiconductor nano-rod with a first surface and a transparent electrode layer at opposite ends thereof, the first surface and the transparent electrode layer being electrically connected to the first electrode portion and the second electrode portion, respectively, and
an insulating cap layer directly between the first conductivity-type semiconductor rod and the transparent electrode, the insulating cap layer overhanging a side surface of the first conductivity-type semiconductor rod,
wherein the first conductivity-type semiconductor rod includes a regrowth layer on the side surface, a combined structure of the regrowth layer with the first conductivity-type semiconductor rod having a hexagonal columnar shape.