Light emitting devices
Light-emitting devices, and related components, systems and methods are disclosed.
1. A light emitting diode comprising:
a first semiconductor layer doped with a first dopant, coupled to a first electrode layer;
an active layer overlying said first semiconductor layer, capable of emitting light;
a second semiconductor layer doped with a second dopant overlying said active layer, said first and second dopants being of opposite type;
a second electrode layer on said second semiconductor layer; and
a periodically-arranged plurality of holes formed in the second semiconductor layer and extending towards the first semiconductor layer, wherein:
the nearest neighbor distance between holes is approximately equal to the wavelength of emitted light;
a depth of at least one of the plurality of holes is such that the thickness of said second semiconductor layer at a bottom of said at least one of the plurality of holes is 40 nm;
a portion of the second electrode layer is disposed in a region of the second semiconductor layer in which a portion of the plurality of holes are formed;
when forward biased, light is emitted from at least a portion of the active layer disposed beneath a portion of the second electrode; and
at least one of said first semiconductor layer, said active layer, and said second semiconductor layer composes a group III element and nitrogen.
2. The light emitting diode of claim 1 , wherein said first dopant is n-type and said second dopant is p-type.
3. The light emitting diode of claim 1 , wherein said first semiconductor layer overlies said first electrode layer.
4. The light emitting diode of claim 1 , wherein said first electrode layer partially overlies said first semiconductor layer; and said first semiconductor layer overlies a substrate with a reflective surface.
5. The light emitting diode of claim 1 , wherein said first electrode layer partially overlies said first semiconductor layer; said second electrode layer is reflective; and said first semiconductor layer overlies a transparent substrate.
6. The light emitting diode of claim 1 , wherein said first semiconductor layer, said active layer, and said second semiconductor layer comprise a group III element and a group V element.
7. The light emitting diode of claim 1 , wherein said first semiconductor layer, said active layer, and said second semiconductor layer comprise GaN.
8. The light emitting diode of claim 1 , wherein said periodically-arranged plurality of holes is periodic in at least one direction parallel to a plane of said second semiconductor layer.
9. The light emitting diode of claim 1 , wherein said periodic arrangement comprises a planar lattice of holes.
10. The light emitting diode of claim 1 , wherein the periodically-arranged plurality of holes form a photonic crystal having a photonic crystal band structure comprising one or more bands with edges; and an energy of said emitted light lies close to an edge of a band of the photonic crystal band structure.
11. The light emitting diode of claim 1 , wherein an intensity of light emitted in a direction normal to a plane of said second semiconductor layer is greater than an intensity of light emitted in a direction different from the normal of the plane of said second semiconductor layer.
12. The light emitting diode of claim 1 , wherein said light emitting diode is disposed in a package, the package comprising: a support frame; a heat sink disposed within said support frame for extracting heat from said light emitting diode, wherein said light emitting diode is disposed over said heat sink; a plurality of leads, electrically coupled to said light emitting diode; and a transparent housing overlying the light emitting diode.