LED including photonic crystal structure
First Claim
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 dopant and said second dopant 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, whereinthe ratio of the period of said periodic arrangement and the wavelength of said emitted light in air is greater than about 0.1 and less than about 5;
a depth of at least one of the plurality of holes is such that a thickness of said second semiconductor layer at a bottom of said at least one of the plurality of the holes is less than about one wavelength of said emitted light in said second semiconductor layer;
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; and
when forward biased, light is emitted from at least a portion of the active layer disposed beneath a portion of the second electrode.
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Accused Products
Abstract
A photonic crystal light emitting diode (“PXLED”) is provided. The PXLED includes a periodic structure, such as a lattice of holes, formed in the semiconductor layers of an LED. The parameters of the periodic structure are such that the energy of the photons, emitted by the PXLED, lies close to a band edge of the band structure of the periodic structure. Metal electrode layers have a strong influence on the efficiency of the PXLEDs. Also, PXLEDs formed from GaN have a low surface recombination velocity and hence a high efficiency. The PXLEDs are formed with novel fabrication techniques, such as the epitaxial lateral overgrowth technique over a patterned masking layer, yielding semiconductor layers with low defect density. Inverting the PXLED to expose the pattern of the masking layer or using the Talbot effect to create an aligned second patterned masking layer allows the formation of PXLEDs with low defect density.
51 Citations
56 Claims
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1. A light emitting diode comprising:
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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 dopant and said second dopant 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 ratio of the period of said periodic arrangement and the wavelength of said emitted light in air is greater than about 0.1 and less than about 5; a depth of at least one of the plurality of holes is such that a thickness of said second semiconductor layer at a bottom of said at least one of the plurality of the holes is less than about one wavelength of said emitted light in said second semiconductor layer; 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; and when forward biased, light is emitted from at least a portion of the active layer disposed beneath a portion of the second electrode. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 43, 44, 45, 49, 50, 51, 52)
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23. A light emitting diode comprising:
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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 ratio of the period of said periodic arrangement and the wavelength of said emitted light in air is greater than about 0.1 and less than about 5; 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 less than about one wavelength of said emitted light in said second semiconductor layer; 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. - View Dependent Claims (24, 25, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 38, 39, 40, 41, 42, 46, 47, 48, 53, 54, 55, 56)
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Specification