Light-emitting device, method of fabricating the device, and LED lamp using the device
A semiconductor light-emitting device has a substrate ( 1 ), a semiconductor layer ( 3 ) and a light-emitting layer ( 5 ), and the substrate is furnished on the surface thereof underlying the semiconductor layer with an irregular construction possessing inclined lateral surfaces forming an angle θ to the substrate in the range of 30°<θ<60°, to provide a light-emitting device enhanced in the effect of fetching light.
1. A light-emitting device comprising a substrate, a semiconductor layer and a light-emitting layer, wherein the substrate and the semiconductor layer superposed thereon differ in refractivity, the substrate is furnished on a surface thereof underlying the semiconductor layer with irregularities possessing inclined lateral surfaces, and the inclined lateral surfaces form an angle θ to the substrate in the range of 30°<θ<60°.
2. The light-emitting device according to claim 1 , wherein the irregularities are V-shaped grooves in a pattern of stripes, laterally inclined projections in a pattern of stripes or laterally inclined pits.
3. The light-emitting device according to claim 2 , wherein the substrate is made of sapphire (Al 2 O 3 ) and the semiconductor layer is made of Al x Ga y In 1−x−y N (0≦x≦1, 0≦y≦1).
4. An LED lamp using the light-emitting device according to claim 3 .
5. An LED lamp using the light-emitting device according to claim 2 .
6. The light-emitting device according to claim 1 , wherein the substrate is made of sapphire (Al 2 O 3 ) and the semiconductor layer is made of Al x Ga y In 1−x−y N (0≦x≦1, 0≦y≦1).
7. An LED lamp using the light-emitting device according to claim 6 .
8. An LED lamp using the light-emitting device according to claim 1 .
9. A light-emitting device comprising a substrate, superposed semiconductor layers and a light-emitting layer, wherein the superposed semiconductor layers mutually differ in refractivity and are furnished on an interface thereof with irregularities possessing inclined lateral surfaces.
10. The light-emitting device according to claim 9 , wherein, the inclined lateral surfaces of the irregularities form an angle θ to the substrate in the range of 30°<θ<60°.
11. The light-emitting device according to claim 10 , wherein the irregularities are V-shaped grooves in a pattern of stripes, laterally inclined projections in a pattern of stripes or laterally inclined pits.
12. The light-emitting device according to claim 11 , wherein the substrate is made of sapphire (Al 2 O 3 ) and the semiconductor layer is made of Al x Ga y In 1−x−y N (0≦x≦1, 0≦y≦1).
13. An LED lamp using the light-emitting device according to claim 12 .
14. An LED lamp using the light-emitting device according to claim 11 .
15. The light-emitting device according to claim 10 , wherein the substrate is made of sapphire (Al 2 O 3 ) and the semiconductor layer is made of Al x Ga y In 1−x−y N (0≦x≦1, 0≦y≦1).
16. An LED lamp using the light-emitting device according to claim 15 .
17. An LED lamp using the light-emitting device according to claim 10 .
18. The light-emitting device according to claim 9 , wherein the irregularities are V-shaped grooves in a pattern of stripes, laterally inclined projections in a pattern of stripes or laterally inclined pits.
19. The light-emitting device according to claim 18 , wherein the substrate is made of sapphire (Al 2 O 3 ) and the semiconductor layer is made of Al x Ga y In 1−x−y N (0≦x≦1, 0≦y≦1).
20. An LED lamp using the light-emitting device according to claim 19 .
21. An LED lamp using the light-emitting device according to claim 18 .
22. The light-emitting device according to claim 9 , wherein the substrate is made of sapphire (Al 2 O 3 ) and the semiconductor layer is made of Al x Ga y In 1−x−y N (0≦x≦1, 0≦y≦1).
23. An LED lamp using the light-emitting device according to claim 22 .
24. An LED lamp using the light-emitting device according to claim 9 .