Light emitting diode containing a grating and methods of making the same
A light emitting diode (LED) includes a n-doped semiconductor material layer, a p-doped semiconductor material layer, an active region disposed between the n-doped semiconductor layer and the p-doped semiconductor layer, and a photonic crystal grating configured to increase the light extraction efficiency of the LED.
1. A light emitting diode (LED), comprising:
a n-doped semiconductor material layer;
a p-doped semiconductor material layer;
an active region disposed between the n-doped semiconductor layer and the p-doped semiconductor layer; and
a photonic crystal grating configured to increase the light extraction efficiency of the LED, wherein the LED has a width of 100 microns or less.
2. The LED of claim 1 , wherein the grating comprises nanostructures configured to guide the light emitted from the active region in a direction substantially perpendicular to a plane of the active region.
3. The LED of claim 2 , further comprising:
a reflector; and
a transparent conductive oxide anode contact located between the reflector and the p-type semiconductor layer,
wherein the nanostructures are located between the reflector and the p-type semiconductor material layer.
4. The LED of claim 3 , wherein the nanostructures are located in the transparent conductive oxide anode contact.
5. A light emitting diode (LED), comprising:
a n-doped semiconductor material layer;
a p-doped semiconductor material layer;
an active region disposed between the n-doped semiconductor layer and the p-doped semiconductor layer; and
a photonic crystal grating configured to increase the light extraction efficiency of the LED, wherein the LED has a width of 100 microns or less, the grating comprises nanostructures configured to guide the light emitted from the active region in a direction substantially perpendicular to a plane of the active region, and the nanostructures are located between the n-doped semiconductor material layer and the active region.
6. The LED of claim 2 , further comprising a buffer semiconductor layer, wherein the n-doped semiconductor material layer is located between the active region and the buffer semiconductor layer.
7. A light emitting diode (LED), comprising:
a n-doped semiconductor material layer;
a p-doped semiconductor material layer;
an active region disposed between the n-doped semiconductor layer and the p-doped semiconductor layer;
a buffer semiconductor layer, wherein the n-doped semiconductor material layer is located between the active region and the buffer semiconductor layer, and
a photonic crystal grating configured to increase the light extraction efficiency of the LED, wherein the LED has a width of 100 microns or less, the grating comprises nanostructures configured to guide the light emitted from the active region in a direction substantially perpendicular to a plane of the active region, and the nanostructures are located on a lower surface of the buffer semiconductor layer opposite to an upper surface facing the active region.
8. A light emitting diode (LED), comprising:
a n-doped semiconductor material layer;
a p-doped semiconductor material layer;
an active region disposed between the n-doped semiconductor layer and the p-doped semiconductor layer;
a buffer semiconductor layer, wherein the n-doped semiconductor material layer is located between the active region and the buffer semiconductor layer, and
a photonic crystal grating configured to increase the light extraction efficiency of the LED, wherein the LED has a width of 100 microns or less, the grating comprises nanostructures configured to guide the light emitted from the active region in a direction substantially perpendicular to a plane of the active region, and the nanostructures are located in the buffer semiconductor layer.
9. A light emitting diode (LED), comprising:
a n-doped semiconductor material layer;
a p-doped semiconductor material layer;
an active region disposed between the n-doped semiconductor layer and the p-doped semiconductor layer;
a buffer semiconductor layer, wherein the n-doped semiconductor material layer is located between the active region and the buffer semiconductor layer, and
a photonic crystal grating configured to increase the light extraction efficiency of the LED, wherein the LED has a width of 100 microns or less, the grating comprises nanostructures configured to guide the light emitted from the active region in a direction substantially perpendicular to a plane of the active region, and the nanostructures are located in the n-doped semiconductor material layer.
10. The LED of claim 1 , wherein the grating comprises:
a photonic crystal layer formed of a dielectric material;
nanostructures comprising holes formed in the photonic crystal layer; and
electrical contacts that extend through the holes in the photonic crystal layer.
11. The LED of claim 1 , wherein:
the grating comprises nanostructures arranged in an array; and
a pitch of the array is at least twice as large as a width of the nanostructures.
12. The LED of claim 11 , wherein:
the nanostructures have the width ranging from about 230 nm to about 740 nm; and
the array has the pitch ranging from about 460 nm to about 1480 nm.
13. The LED of claim 1 , wherein the grating comprises nanostructures comprising:
(i) transparent conductive oxide pillars, or
(ii) holes in a transparent conductive oxide photonic crystal layer.
14. The LED of claim 1 , wherein the grating comprises nanostructures comprising:
(i) polymer pillars; or
(ii) holes in a polymer photonic crystal layer.
15. A method of forming a light emitting diode (LED), comprising:
forming a n-doped semiconductor material layer over a substrate;
forming an active region over the n-doped semiconductor material layer;
forming a p-doped semiconductor material layer over the active region;
forming a reflector over the p-doped semiconductor material layer; and
forming a photonic crystal grating configured to increase the light extraction efficiency of the LED, wherein the LED has a width of 100 microns or less.
16. The method of claim 15 , wherein the grating comprises nanostructures configured to guide the light emitted from the active region in a direction substantially perpendicular to a plane of the active region.
17. The method of claim 16 , wherein the nanostructures are located between the reflector and the p-type semiconductor region.
18. The method of claim 17 , further comprising forming a transparent conductive oxide anode contact over the p-type semiconductor layer, wherein the nanostructures are located in the transparent conductive oxide anode contact.
19. A method of forming a light emitting diode (LED), comprising:
forming a n-doped semiconductor material layer over a substrate;
forming an active region over the n-doped semiconductor material layer;
forming a p-doped semiconductor material layer over the active region;
forming a reflector over the p-doped semiconductor material layer; and
forming a photonic crystal grating configured to increase the light extraction efficiency of the LED, wherein the LED has a width of 100 microns or less, wherein the grating comprises nanostructures configured to guide the light emitted from the active region in a direction substantially perpendicular to a plane of the active region, and the nanostructures are located between the n-doped semiconductor material layer and the active region.
20. A method of forming a light emitting diode (LED), comprising:
forming a n-doped semiconductor material layer over a substrate;
forming an active region over the n-doped semiconductor material layer;
forming a p-doped semiconductor material layer over the active region;
forming a reflector over the p-doped semiconductor material layer;
forming a photonic crystal grating configured to increase the light extraction efficiency of the LED, wherein the LED has a width of 100 microns or less, wherein the grating comprises nanostructures configured to guide the light emitted from the active region in a direction substantially perpendicular to a plane of the active region; and
forming a buffer semiconductor layer, such that the n-doped semiconductor material layer is formed over an upper surface of the buffer semiconductor layer,
wherein the nanostructures are located on a lower surface of the buffer semiconductor layer opposite to the upper surface, in the buffer semiconductor layer, or in the n-doped semiconductor material layer.
21. The method of claim 20 , further comprising forming airgaps in the photonic crystal grating between the buffer semiconductor layer and the n-doped semiconductor material layer.
22. The LED of claim 1 , wherein the LED has a width between 1 micron and 20 microns.
23. The method of claim 15 , wherein the LED has a width between 1 micron and 20 microns.