Optoelectronic device and the manufacturing method thereof
The present disclosure is related to an optoelectronic device comprising a semiconductor stack comprising a first surface and a second surface opposite to the first surface; a first contact layer on the first surface; and a second contact layer on the second surface, wherein the second contact layer is not overlapped with the first contact layer in a vertical direction; wherein the second contact layer comprises a plurality of dots separating from each other and formed of semiconductor material.
1. An optoelectronic device comprising:
a semiconductor stack comprising a first surface and a second surface opposite to the first surface;
a first contact layer on the first surface; and
a second contact layer on the second surface and comprising an impurity concentration increasing in a direction from the semiconductor stack toward the second contact layer,
wherein the second contact layer comprises a plurality of dots separating from each other and formed of semiconductor material.
2. The optoelectronic device of claim 1 , wherein the highest impurity concentration is equal to or larger than 1*10 19 cm −3 , and the lowest impurity concentration is equal to or lower than 1*10 18 cm −3 .
3. The optoelectronic device of claim 1 , wherein the second contact layer comprises GaP.
4. The optoelectronic device of claim 1 , wherein one of the dots has a width between 5 μm and 15 μm both inclusive.
5. The optoelectronic device of claim 1 , wherein one of the dots has a thickness is between 100 Ř10000 Šboth inclusive.
6. The optoelectronic device of claim 1 , wherein one of the dots comprises a side surface and a top surface substantially parallel to the second surface, wherein an angle between the side surface and the second surface is equal to or larger than 90 degree.
7. The optoelectronic device of claim 6 , further comprising an insulating layer on the second surface and contacting the side surface.
8. The optoelectronic device of claim 7 , wherein the insulating layer covers a portion of the top surface.
9. The optoelectronic device of claim 7 , wherein the insulating layer comprises a refractive index between 1.3˜1.6 both inclusive.
10. The optoelectronic device of claim 7 , wherein the thickness of the insulating layer is equal to or smaller than the thickness of the one of the dots.
11. The optoelectronic device of claim 6 , further comprising a transparent conductive layer on the plurality of dots.
12. The optoelectronic device of claim 11 , wherein the transparent conductive layer has a surface opposite to the plurality of dots, and a roughness average (Ra) of the surface is equal to or lower than 2 nm.
13. The optoelectronic device of claim 12 , further comprising a reflecting layer on the surface of the transparent conductive layer.
14. The optoelectronic device of claim 13 , further comprising a substrate on the reflecting layer.
15. The optoelectronic device of claim 14 , further comprising a metal layer between and bonding the reflecting layer and the substrate.
16. The optoelectronic device of claim 14 , wherein the substrate comprises Si.
17. The optoelectronic device of claim 15 , wherein the metal layer comprises In, Au, Sn, Pb, InAu, SnAu, or the alloy thereof.
18. The optoelectronic device of claim 1 , wherein the second contact layer comprises a tunnel junction structure.