Laser diode having nano patterns and method of fabricating the same
View Patent ↗A laser diode having nano patterns is disposed on a substrate. A first conductive-type clad layer is disposed on the substrate, and a second conductive-type clad layer is disposed on the first conductive-type clad layer. An active layer is interposed between the first conductive-type clad layer and the second conductive-type clad layer. Column-shaped nano patterns are arranged at a surface of the second conductive-type clad layer to form a laser diode such as a distributed feedback laser diode.
1. A laser diode, comprising:
a substrate;
a first conductive-type clad layer disposed on the substrate;
a second conductive-type clad layer disposed on the first conductive-type clad layer;
an active layer interposed between the first conductive-type clad layer and the second conductive-type clad layer; and
column-shaped nano patterns arranged at a surface of the second conductive-type clad layer,
wherein the nano patterns are protruding columns including the second conductive-type clad layer and a second conductive-type contact layer,
wherein the nano patterns are formed in a protruding column shape,
wherein the second conductive-type contact layer is disposed on an upper side of the nano patterns.
2. The laser diode as claimed in claim 1 , wherein the nano patterns are formed by partially etching the second conductive-type clad layer.
3. The laser diode as claimed in claim 1 , wherein the respective nano patterns are formed in a circular-column shape having a diameter.
4. The laser diode as claimed in claim 3 , wherein the nano patterns are spaced apart from one another at an interval equal to the diameter.
5. The laser diode as claimed in claim 4 , wherein the diameter is 100 nm to 250 nm.
6. The laser diode as claimed in claim 4 , wherein cleavage mirrors are respectively formed at both opposite side surfaces of the laser diode.
7. The laser diode as claimed in claim 1 , wherein the laser diode is one of a distributed feedback laser diode, a distributed Bragg reflector laser diode, and a Bragg reflector laser diode.
8. The laser diode as claimed in claim 6 , wherein each cleavage mirror is parallel with any one side of a regular triangle defined by three adjacent nano patterns.
9. The laser diode as claimed in claim 6 , wherein each cleavage mirror makes an angle of intersection with all sides of a regular triangle defined by three adjacent nano patterns.
10. A laser diode, comprising:
a substrate;
a first conductive-type clad layer disposed on the substrate;
a second conductive-type clad layer disposed on the first conductive-type clad layer;
a second conductive-type contact layer disposed on the second conductive-type clad layer;
an active layer interposed between the first conductive-type clad layer and the second conductive-type clad layer; and
column-shaped nano patterns arranged at a surface of the second conductive-type clad layer,
wherein the nano patterns are recessed portions surrounded by the second conductive-type clad layer and the second conductive-type contact layer on at least two adjacent sides of each nano pattern,
wherein a bottom surface of the recessed portions comprises the second conductive-type clad layer, and
wherein the nano patterns are recessed portions disposed in the second conductive-type clad layer through the second conductive-type contact layer.
11. The laser diode as claimed in claim 10 , wherein the nano patterns are formed by partially etching the second conductive-type clad layer.
12. The laser diode as claimed in claim 10 , wherein the respective nano patterns are formed in a circular-column shape having a diameter.
13. The laser diode as claimed in claim 12 , wherein the nano patterns are spaced apart from one another at an interval equal to the diameter.
14. The laser diode as claimed in claim 13 , wherein the diameter is 100 nm to 250 nm.
15. The laser diode as claimed in claim 13 , wherein cleavage mirrors are respectively formed at both opposite side surfaces of the laser diode.
16. The laser diode as claimed in claim 10 , wherein the laser diode is one of a distributed feedback laser diode, a distributed Bragg reflector laser diode, and a Bragg reflector laser diode.
17. A method for fabricating a laser diode, comprising:
forming semiconductor layers with a laminated structure comprising a first conductive-type clad layer, an active layer, and a second conductive-type clad layer on a substrate;
forming a second conductive-type contact layer on the second conductive-type clad layer; and
forming column-shaped nano patterns spaced apart from one another by partially etching the second conductive-type clad layer and the second conductive-type contact layer,
wherein the nano patterns are protruding columns including the second conductive-type clad layer and the second conductive-type contact layer or are recessed portions surrounded by the second conductive-type clad layer and the second conductive-type contact layer on at least two adjacent sides of each nano pattern, and
wherein a bottom surface of the recessed portions comprises the second conductive-type clad layer.
18. The method as claimed in claim 17 , wherein the nano patterns are formed using a nano imprint technique.
19. The method as claimed in claim 17 , wherein the nano patterns are arranged so that three adjacent nano patterns define a regular triangle.
20. The method as claimed in claim 19 , wherein cleavage mirrors are respectively formed at both opposite side surfaces of the laser diode by cleaving the substrate.
21. The laser diode as claimed in claim 20 , wherein the cleavage mirrors are parallel with any one side of a regular triangle defined by three adjacent nano patterns.
22. The laser diode as claimed in claim 20 , wherein the cleavage mirrors make an angle of intersection with all sides of a regular triangle defined by three adjacent nano patterns.