Indium gallium nitride red light emitting diode and method of making thereof
A red-light emitting diode includes an n-doped portion, a p-doped portion, and a light emitting region located between the n-doped portion and a p-doped portion. The light emitting region includes a light-emitting indium gallium nitride layer emitting light at a peak wavelength between 600 and 750 nm under electrical bias thereacross, an aluminum gallium nitride layer located on the light-emitting indium gallium nitride layer and a GaN barrier layer located on the aluminum gallium nitride layer.
1. A red-light emitting diode, comprising:
an n-doped portion comprising a single crystalline n-doped GaN layer;
a p-doped portion;
a light emitting region located between the n-doped portion and a p-doped portion, the light emitting region comprising:
a light-emitting indium gallium nitride layer emitting light at a peak wavelength between 600 and 750 nm under electrical bias thereacross;
a III-nitride layer located on the light-emitting indium gallium nitride layer; and
a GaN barrier layer located on the III-nitride layer; and
at least one strain-modulating layer located between the single crystalline n-doped GaN layer and the light emitting region, wherein the at least one strain-modulating layer comprises a plurality of strain-modulating layer stacks that are located on the single crystalline n-doped GaN layer and comprise a respective intervening indium gallium nitride layer and a respective intervening GaN layer;
wherein:
an effective lattice constant of each strain-modulating layer stack of the plurality of strain-modulating layer stacks monotonically increases with a distance from the single crystalline n-doped GaN layer; and
an atomic concentration of indium in the intervening indium gallium nitride layers of the plurality of strain-modulating layer stacks monotonically increases with a physical distance of each strain-modulating layer stack from the single crystalline n-doped GaN layer; and
wherein the light emitting diode comprises at least one feature selected from:
(a) the light emitting diode comprises a nanowire device; or
(b) the light emitting region consists of one or two quantum wells; or
(c) the III-nitride layer comprises an aluminum gallium nitride layer which has a composition Al y Ga (1-y) N, where y is in a range from 0.3 to 1.0; or
(d) a UV emitting InGaN/GaN superlattice is located between the n-doped portion and the light emitting region.
2. The light emitting diode of claim 1 , wherein the p-doped portion comprises a p-doped III-nitride layer which comprises a p-doped aluminum gallium nitride layer.
3. The light emitting diode of claim 1 , wherein:
the light-emitting indium gallium nitride layer has a composition of In x Ga (1-x) N, wherein x is in a range from 0.26 to 0.55; and
the light-emitting indium gallium nitride layer has a thickness in a range from 3 nm to 7 nm.
4. The light emitting diode of claim 3 , wherein the p-doped III-nitride layer comprises a p-doped aluminum gallium nitride layer which has a thickness in a range from 0.5 nm to 5.0 nm and the GaN barrier layer has a thickness in a range from 5 nm to 20 nm.
5. The light emitting diode of claim 4 , further comprising a p-doped GaN layer located on the p-doped aluminum gallium nitride layer.
6. The light emitting diode of claim 1 , wherein:
the single crystalline n-doped GaN layer has a planar top surface; and
each layer within the plurality of strain-modulating layer stacks, the light-emitting indium gallium nitride layer, the III-nitride layer, and the GaN barrier layer are planar layers having a respective top surface and a respective bottom surface that are parallel to the planar top surface of the single crystalline n-doped GaN layer.
7. The light emitting diode of claim 1 wherein the light emitting diode comprises feature (a).
8. The light emitting diode of claim 1 wherein the light emitting diode comprises feature (b).
9. The light emitting diode of claim 1 wherein the light emitting diode comprises feature (c).
10. The light emitting diode of claim 1 wherein the light emitting diode comprises feature (d).
11. The light emitting diode of claim 1 wherein the light emitting diode comprises two or more of features (a) to (d).
12. The light emitting diode of claim 1 , wherein the red-light emitting diode comprises a first light emitting diode which has a width between 1 and 100 microns located in a direct view display on a backplane, which further comprises a second green-light emitting light emitting diode a third blue-light emitting diode located on the backplane.
13. The light emitting diode of claim 1 , wherein the light-emitting indium gallium nitride layer emits light at a peak wavelength between 610 and 650 nm under electrical bias thereacross.
14. A red-light emitting diode, comprising:
an n-doped portion;
a p-doped portion;
a light emitting region located between the n-doped portion and a p-doped portion, the light emitting region comprising:
a light-emitting indium gallium nitride layer emitting light at a peak wavelength between 600 and 750 nm under electrical bias thereacross;
a III-nitride layer located on the light-emitting indium gallium nitride layer; and
a GaN barrier layer located on the III-nitride layer; and
at least one strain-modulating layer located between the n-doped portion and the light emitting region, wherein the at least one strain-modulating layer comprises a plurality of strain-modulating layer stacks that are located on the n-doped portion and comprise a respective intervening indium gallium nitride layer and a respective intervening GaN layer;
wherein the light emitting diode comprises at least one feature selected from:
(a) the light emitting diode comprises a nanowire device; or
(b) the light emitting region consists of one or two quantum wells; or
(c) the III-nitride layer comprises an aluminum gallium nitride layer which has a composition Al y Ga (1-y) N, where y is in a range from 0.3 to 1.0; or
(d) a UV emitting InGaN/GaN superlattice is located between the n-doped portion and the light emitting region;
wherein:
the n-doped portion comprises a single crystalline n-doped GaN portion which is a nanowire core that protrudes vertically from a horizontal surface of a single crystalline n-doped GaN layer having a planar top surface;
each layer within the plurality of strain-modulating layer stacks, the light-emitting indium gallium nitride layer, the III-nitride layer, and the GaN barrier layer laterally surrounds the nanowire core and includes vertical portions that extend along a vertical direction and perpendicular to the planar top surface of the single crystalline n-doped GaN layer; and
light-emitting indium gallium nitride layer contains an indium rich nano-ring region which a structural discontinuity between p-plane and m-plane portions of the light-emitting indium gallium nitride layer and includes at least 5 atomic percent higher indium content than the p-plane and the m-plane portions of the light-emitting indium gallium nitride layer such that the nano-ring region has a composition of In x Ga (1-x) N, in which x is in a range from 0.26 to 0.55.
15. A red-light emitting diode, comprising:
an n-doped portion;
a p-doped portion; and
a light emitting region located between the n-doped portion and a p-doped portion, the light emitting region comprising a light-emitting indium gallium nitride layer emitting light at a peak wavelength between 610 and 650 nm under electrical bias thereacross;
wherein:
the light emitting diode comprises a micro-light emitting diode having a lateral dimension in a range from 1 micron to 100 microns;
the light emitting diode is located in a display device; and
the light emitting diode emits the light at the peak wavelength between 610 and 650 nm under electrical bias thereacross having a full width half maximum of 100 nm or less and an external quantum efficiency of 2 to 10% for current densities of 1 to 2 A/cm 2 .
16. The light emitting diode of claim 15 , wherein the light emitting region further comprises
a III-nitride layer located on the light-emitting indium gallium nitride layer; and
a GaN barrier layer located on the III-nitride layer.
17. The light emitting diode of claim 15 , wherein:
the light emitting diode emits the light at the peak wavelength between 615 and 630 nm under electrical bias thereacross having a full width half maximum of 45 to 50 nm and an external quantum efficiency of 2 to 3.9% for the current densities of 1 to 2 A/cm 2 ; and
the display device comprises an in-eye projection device comprising the light emitting diode as a single red sub-pixel, a monocolor display device formed on a backplane, or an RGB monolithic display device.
18. A red-light emitting diode, comprising:
an n-doped portion;
a p-doped portion; and
a light emitting region located between the n-doped portion and a p-doped portion, the light emitting region comprising a light-emitting indium gallium nitride layer emitting light at a peak wavelength between 610 and 650 nm under electrical bias thereacross;
wherein:
the light emitting diode comprises a micro-light emitting diode having a lateral dimension of 100 microns or less;
the light emitting diode is located in a display device; and
the light emitting diode emits the light at the peak wavelength between 610 and 650 nm under electrical bias thereacross having a full width half maximum of 100 nm or less and an external quantum efficiency of 2 to 10% for current densities of 2 A/cm 2 or less.
19. The light emitting diode of claim 18 , wherein the light emitting region further comprises
a III-nitride layer located on the light-emitting indium gallium nitride layer; and
a GaN barrier layer located on the III-nitride layer.
20. The light emitting diode of claim 18 , wherein:
the light emitting diode emits the light at the peak wavelength between 610 and 650 nm under electrical bias thereacross having the full width half maximum of 100 nm or less and the external quantum efficiency of 2 to 10% for current densities below 1 A/cm 2 ; and
the display device comprises an in-eye projection device comprising the light emitting diode as a single red sub-pixel, a monocolor display device formed on a backplane, or an RGB monolithic display device.