Semiconductor light emitting device having a rod shape, and display apparatus including the same
A semiconductor light emitting device includes a light emitting structure having a rod shape with first and second surfaces opposing each other and a side surface connected between the first and second surfaces, and including a first conductivity-type semiconductor providing the first surface, an active layer and a second conductivity-type semiconductor, a first electrode layer on a first region of the first surface of the light emitting structure and connected to the first conductivity-type semiconductor, the first region having a level that is vertically offset from a level of a second region adjacent thereto, and a second electrode layer connected to the second conductivity-type semiconductor.
1. A semiconductor light emitting device, comprising:
a light emitting structure having a rod shape with first and second surfaces opposing each other and a side surface connected between the first and second surfaces, and including a first conductivity-type semiconductor providing the first surface, an active layer, and a second conductivity-type semiconductor;
a first electrode layer on a first region of the first surface of the light emitting structure and connected to the first conductivity-type semiconductor, the first region having a level that is vertically offset from a level of a second region adjacent thereto; and
a second electrode layer connected to the second conductivity-type semiconductor,
wherein the first electrode layer has a ring shape surrounding the second region, and contacts the first region,
wherein the light emitting structure has a hexagonal columnar structure, and the first electrode layer has a width greater than a width of the first surface of the light emitting structure.
2. The semiconductor light emitting device as claimed in claim 1 , wherein the first surface of the light emitting structure is a non-flat surface from which the second region protrudes, and the second surface of the light emitting structure is a flat surface.
3. The semiconductor light emitting device as claimed in claim 1 , wherein the second region of the first surface protrudes beyond the first electrode layer.
4. The semiconductor light emitting device as claimed in claim 1 , wherein the second region of the first surface is a cleavage plane of the first conductivity-type semi conductor.
5. The semiconductor light emitting device as claimed in claim 1 , wherein the first region surrounds the second region.
6. The semiconductor light emitting device as claimed in claim 1 , wherein:
the first electrode layer includes an ohmic contact layer connected to the first surface of the first conductivity-type semiconductor, and
the ohmic contact layer includes at least one of silver (Ag), copper (Cu), palladium (Pd), platinum (Pt), tin (Sn), tungsten (W), rhodium (Rh), iridium (Ir), ruthenium (Ru), magnesium (Mg), zinc (Zn), or alloy materials thereof.
7. The semiconductor light emitting device as claimed in claim 6 , wherein the first electrode layer further includes a metal nitride layer disposed on the ohmic contact layer.
8. The semiconductor light emitting device as claimed in claim 6 , wherein the ohmic contact layer includes W or WSi.
9. The semiconductor light emitting device as claimed in claim 1 , wherein the second electrode layer includes a transparent electrode material.
10. The semiconductor light emitting device as claimed in claim 1 , wherein the first and second conductivity-type semiconductors and the active layer are nitride semiconductors.
11. The semiconductor light emitting device as claimed in claim 1 , wherein the first conductivity-type semiconductor and the second conductivity-type semiconductor provide the first and second surfaces, respectively, and the active layer is disposed between the first and second conductivity-type semiconductors.
12. The semiconductor light emitting device as claimed in claim 1 , wherein the first conductivity-type semiconductor has the rod shape, and
the active layer and the second conductivity-type semiconductor are sequentially stacked on a portion of a side surface of the first conductivity-type semiconductor, adjacent to the second surface.
13. The semiconductor light emitting device as claimed in claim 1 , wherein each of the first conductivity-type semiconductor, the active layer, and the second conductivity-type semiconductor is hexagonal and has a same width in a horizontal direction.
14. A display apparatus, comprising:
a plurality of pixels; and
a first electrode portion and a second electrode portion disposed in a pixel among the plurality of pixels, the first electrode portion being spaced apart from the second electrode portion with the semiconductor light emitting device as claimed in claim 1 disposed therebetween such that the first electrode layer of the semiconductor light emitting device is connected to the first electrode portion and the second electrode layer of the semiconductor light emitting device is connected to the second electrode portion.
15. A semiconductor light emitting device, comprising:
a light emitting structure having a rod shape with first and second surfaces opposing each other and a side surface connected between the first and second surfaces, and including first and second conductivity-type semiconductor layers providing the first and second surfaces, respectively, and an active layer disposed between the first and second conductivity-type semiconductor layers;
a first electrode layer connected to the first conductivity-type semiconductor layer and disposed on a first region of the first surface of the light emitting structure, the first region having a level that is vertically offset relative to a level of a second region adjacent thereto; and
a second electrode layer on the second surface of the light emitting structure and connected to the second conductivity-type semiconductor layer,
wherein the light emitting structure has a hexagonal columnar structure,
wherein the first electrode layer has a circular ring shape, and has a width greater than a width of the first surface of the light emitting structure.
16. The semiconductor light emitting device as claimed in claim 15 , wherein the first surface of the light emitting structure is a non-flat surface from which the second region protrudes, and the second surface of the light emitting structure is a flat surface.
17. The semiconductor light emitting device as claimed in claim 15 , wherein the first electrode layer has a ring shape, and the second electrode layer is disposed on substantially all of the second surface of the light emitting structure.
18. The semiconductor light emitting device as claimed in claim 15 , further comprising a passivation layer surrounding the side surface of the light emitting structure.