Semiconductor light-emitting device
A semiconductor light-emitting device capable of attaining a surface plasmon effect while attaining excellent ohmic contact is provided. This semiconductor light-emitting device comprises a semiconductor layer formed on an emission layer, a first electrode layer formed on the semiconductor layer and a second electrode layer, formed on the first electrode layer, having a periodic structure. The first electrode layer is superior to the second electrode layer in ohmic contact with respect to the semiconductor layer, and the second electrode layer contains a metal exhibiting a higher plasma frequency than the first electrode layer.
1. A semiconductor light-emitting device comprising:
a semiconductor layer formed on an emission layer;
a first electrode layer formed on said semiconductor layer; and
a second electrode layer, formed on said first electrode layer, having a periodic structure, wherein
said first electrode layer is superior to said second electrode layer in ohmic contact with respect to said semiconductor layer, and
said second electrode layer contains a metal exhibiting a higher plasma frequency than said first electrode layer.
2. The semiconductor light-emitting device according to claim 1 , wherein
said semiconductor layer is a p-type nitride-based semiconductor layer, and
said first electrode layer is formed to be in contact with said p-type nitride-based semiconductor layer.
3. The semiconductor light-emitting device according to claim 1 , wherein
said periodic structure of said second electrode layer is a periodic corrugated shape.
4. The semiconductor light-emitting device according to claim 3 , wherein
said periodic structure of said second electrode layer includes a structure obtained by periodically arranging recess portions or projection portions of said corrugated shape in the form of a triangular lattice.
5. The semiconductor light-emitting device according to claim 3 , wherein
said periodic structure of said second electrode layer includes a striped periodic structure.
6. The semiconductor light-emitting device according to claim 5 , wherein
said semiconductor layer has a projecting ridge portion, and
said second electrode layer having said striped periodic structure is formed on said ridge portion of said semiconductor layer along the extensional direction of said ridge portion.
7. The semiconductor light-emitting device according to claim 1 , wherein
said semiconductor layer includes a surface formed with a periodic corrugated shape.
8. The semiconductor light-emitting device according to claim 7 , wherein
recess portions or projection portions of said surface of said semiconductor layer formed with said periodic corrugated shape are periodically arranged in the form of a triangular lattice.
9. The semiconductor light-emitting device according to claim 1 , wherein
said first electrode layer has a smaller thickness than said second electrode layer.
10. The semiconductor light-emitting device according to claim 1 , wherein
said first electrode layer is made of at least one of Ni, Pd and Pt, and
said second electrode layer is made of at least either Al or Ag.
11. The semiconductor light-emitting device according to claim 10 , wherein
said first electrode layer contains Pd, and
said second electrode layer contains Ag.
12. The semiconductor light-emitting device according to claim 10 , wherein
said first electrode layer contains Pt, and
said second electrode layer contains Al.
13. The semiconductor light-emitting device according to claim 10 , wherein
said first electrode layer contains Ni, and
said second electrode layer contains Ag.
14. The semiconductor light-emitting device according to claim 1 , wherein
said first electrode layer has said periodic structure, and
said second electrode layer having said periodic structure is formed on said first electrode layer to reflect said periodic structure of said first electrode layer.
15. The semiconductor light-emitting device according to claim 14 , wherein
said first electrode layer and said second electrode layer are formed with the same periodic corrugated shapes.
16. The semiconductor light-emitting device according to claim 14 , wherein
said second electrode layer is formed with a periodic corrugated shape on the interface between said second electrode layer and said first electrode layer.
17. The semiconductor light-emitting device according to claim 1 , further comprising a protective layer formed on said second electrode layer.
18. The semiconductor light-emitting device according to claim 1 , extracting light emitted from said emission layer through a region formed with said second electrode layer having said periodic structure.
19. The semiconductor light-emitting device according to claim 1 , extracting light emitted from said emission layer through a region opposite to a region formed with said second electrode layer having said periodic structure.
20. The semiconductor light-emitting device according to claim 1 , wherein
said semiconductor layer includes a ZnO layer.