Light-emitting device

1. A light-emitting device, comprising:

an epitaxial structure comprising a lower cladding layer of first conductivity type, an active layer comprising InGaN or AlGaInN on the lower cladding layer, and an upper cladding layer of second conductivity type on the active layer;

a tunneling structure on the epitaxial structure comprising a first tunneling layer of second conductivity type with a doping concentration greater than 6×10 19 /cm 3 on the upper cladding layer, and a second tunneling layer of first conductivity type with a doping concentration greater than 6×10 19 /cm 3 on the first tunneling layer; and

a current spreading layer of first conductivity type comprising AlInN on the tunneling structure.

2. The light-emitting device according to claim 1 , wherein the thickness of the first tunneling layer is about 100 to 500 angstroms and the doping concentration thereof is about 6×10 19 /cm 3 to 1×10 20 /cm 3 .

3. The light-emitting device according to claim 1 , wherein the thickness of the second tunneling layer is about 100 to 500 angstroms and the doping concentration thereof is about 2×10 20 /cm 3 to 3×10 20 /cm 3 .

4. The light-emitting device according to claim 1 , wherein the thickness of the current spreading layer is about 0.1 to 5 micrometers.

5. The light-emitting device according to claim 1 , wherein the first conductivity type is n-type.

6. The light-emitting device according to claim 1 , wherein the material of the lower cladding layer comprises AlInN.

7. The light-emitting device according to claim 1 , wherein the material of the first tunneling layer comprises AlInN.

8. The light-emitting device according to claim 1 , wherein the material of the second tunneling layer comprises AlInN.

9. The light-emitting device according to claim 1 , further comprising:

an electrically conductive permanent substrate; and

an adhesive layer connected with the electrically conductive permanent substrate and the epitaxial structure.

10. The light-emitting device according to claim 9 , wherein the material of the electrically conductive permanent substrate is selected from the group consisting of silicon, capper, aluminum, molybdenum, gold, silver, silicon carbide, aluminum nitride, and gallium nitride.

11. The light-emitting device according to claim 9 , wherein the material of the adhesive layer is selected from the group consisting of solder, low temperature metal, metal silicone, spontaneous electrically conductive polymer or polymer doped aluminum, gold, platinum, zinc, silver, nickel, germanium, indium, tin, titanium, tin, titanium, lead, copper, palladium and the alloys.

12. The light-emitting device according to claim 9 , further comprising an isolation layer disposed between the electrically conductive permanent substrate and the adhesive layer.

13. A light-emitting device, comprising:

an epitaxial structure comprising a lower cladding layer of the first conductivity type, an active layer comprising InGaN or AlGaInN on the lower cladding layer, and an upper cladding layer of second conductivity type on the active layer;

a tunneling structure on the epitaxial structure comprising a first tunneling layer of second conductivity type with a doping concentration greater than 6×10 19 /cm 3 on the upper cladding layer, and a second tunneling layer of first conductivity type with a doping concentration greater than 6×10 19 /cm 3 on the first tunneling layer; and

a current spreading layer of first conductivity type comprising AlInN on the tunneling structure,

wherein the material of the upper cladding layer comprises AlInN.

14. A light-emitting device, comprising:

an epitaxial structure comprising, a lower cladding layer of first conductivity type, an active layer comprising InGaN or AlGaInN on the lower cladding layer, and an upper cladding layer of second conductivity type on the active layer;

a tunneling structure on the epitaxial structure comprising a first tunneling layer of second conductivity type with a doping concentration greater than 6×10 19 /cm 3 on the upper cladding layer, and a second tunneling layer of first conductivity type with a doping concentration greater than 6×10 19 /cm 3 on the first tunneling layer;

a current spreading layer of first conductivity type comprising AlInN on the tunneling structure;

an electrically conductive permanent substrate;

an adhesive layer connected with the electrically conductive permanent substrate and the epitaxial structure; and

an isolation layer disposed between the electrically conductive permanent substrate and the adhesive layer,

wherein the material of the isolation layer comprises aluminum oxide, silicon oxide, silicon nitride, or aluminum nitride.