Semiconductor light-emitting device
A semiconductor light-emitting device comprises an epitaxial structure comprising an main light-extraction surface, a lower surface opposite to the main light-extraction surface, a side surface connecting the main light-extraction surface and the lower surface, a first portion and a second portion between the main light-extraction surface and the first portion, wherein a concentration of a doping material in the second portion is higher than that of the doping material in the first portion and, in a cross-sectional view, the second portion comprises a first width near the main light-extraction surface and second width near the lower surface, and the first width is smaller than the second width.
1. A light-emitting device comprising:
an epitaxial structure having a first thickness and an upper surface with a circumference, comprising:
a first semiconductor stack;
an active layer on the first semiconductor stack; and
a second semiconductor stack on the active layer and having a second thickness not larger than 1 μm;
wherein a ratio of the first thickness to the circumference is between 2% and 20%.
2. The light-emitting device according to claim 1 , wherein an area of the upper surface is smaller than 10000 μm 2 .
3. The light-emitting device according to claim 1 , wherein the circumference is smaller than 400 μm.
4. The light-emitting device according to claim 1 , wherein the epitaxial structure is devoid of a distributed Bragg reflector between the active layer and the upper surface.
5. The light-emitting device according to claim 1 , wherein the upper surface has a square shape.
6. The light-emitting device according to claim 1 , wherein the circumference is smaller than 354 μm.
7. The light-emitting device according to claim 1 , wherein the second semiconductor stack comprises three semiconductor layers, one of which has a thickness less than 2000 Å.
8. The light-emitting device according to claim 1 , wherein the first thickness is smaller than 3 μm.
9. The light-emitting device according to claim 1 , wherein the active layer comprises a multiple quantum well structure.
10. The light-emitting device according to claim 1 , wherein the first semiconductor stack, the active layer and the second semiconductor stack comprise an III-V semiconductor material.
11. The light-emitting device according to claim 1 , wherein the first semiconductor stack is a p-type semiconductor and the second semiconductor stack is an n-type semiconductor.
12. The light-emitting device according to claim 1 , further comprising a first electrode contacts the first semiconductor stack.
13. The light-emitting device according to claim 12 , further comprising a second electrode contacts the second semiconductor stack.
14. The light-emitting device according to claim 1 , wherein the light-emitting device has a current density between 0.1 A/cm 2 and 1 A/cm 2 .
15. A light-emitting device comprising:
an epitaxial structure having a first thickness and an upper surface with a circumference, comprising:
a first semiconductor stack;
an active layer on the first semiconductor stack; and
a second semiconductor stack on the active layer and having a second thickness not larger than 1 μm;
wherein a ratio of the first thickness to the circumference is smaller than 0.75%.
16. The light-emitting device according to claim 14 , wherein an area of the upper surface is smaller than 10000 μm 2 .
17. The light-emitting device according to claim 14 , wherein the circumference is smaller than 400 μm.
18. The light-emitting device according to claim 14 , wherein the upper surface has a square shape.
19. The light-emitting device according to claim 14 , wherein the circumference is smaller than 354 μm.
20. The light-emitting device according to claim 14 , wherein the first thickness is smaller than 3 μm.