Semiconductor light emitting device
First Claim
1. A light emitting device comprising:
- a substrate layer;
a first layer which is disposed above the substrate layer, and which comprises at least one layer including a semiconductor cladding layer of a first conductivity type;
an active layer disposed above the first layer; and
a second layer which is disposed above the active layer, and which comprises at least one layer including a semiconductor cladding layer of a second conductivity type, the second layer having a two-dimensional periodic structure in a surface thereof,wherein the first layer includes at least one layer having a refractive index that is lower than a refractive index of the active layer and lower than a refractive index of a layer of the second layer that is adjacent to the active layer, and wherein each constituent layer of the second layer has a lower refractive index than the active layer.
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Abstract
A light emitting device with an increased light extraction efficiency includes a two-dimensional periodic structure in a surface thereof and has two layers that together form an asymmetric refractive index distribution with respect to the active layer, which is in between the two layers. The light emitting device includes a substrate layer, a first layer, an active layer and a second layer that are stacked sequentially. The first layer includes at least one layer, including a semiconductor cladding layer of a first conductivity type. At least one layer of the first layer has a refractive index that is lower than a refractive index of the active layer and lower than a refractive index of a layer of the second layer that is adjacent to the active layer. Each constituent layer of the second layer has a refractive index that is lower than the refractive index of the active layer.
44 Citations
25 Claims
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1. A light emitting device comprising:
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a substrate layer; a first layer which is disposed above the substrate layer, and which comprises at least one layer including a semiconductor cladding layer of a first conductivity type; an active layer disposed above the first layer; and a second layer which is disposed above the active layer, and which comprises at least one layer including a semiconductor cladding layer of a second conductivity type, the second layer having a two-dimensional periodic structure in a surface thereof, wherein the first layer includes at least one layer having a refractive index that is lower than a refractive index of the active layer and lower than a refractive index of a layer of the second layer that is adjacent to the active layer, and wherein each constituent layer of the second layer has a lower refractive index than the active layer. - View Dependent Claims (3, 5, 7, 11, 13, 14)
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2. A light emitting device comprising:
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a substrate layer; a first layer which comprises at least one layer and which is disposed above the substrate layer; an active layer which has a multiple quantum well structure and which is disposed above the first layer; and a second layer which comprises at least one layer and which is disposed above the active layer, the second layer having a two-dimensional periodic structure in a surface thereof, wherein the first layer includes at least one layer having a refractive index that is lower than a thickness-weighted-average of refraction indices of the active layer and lower than a refractive index of a layer of the second layer that is adjacent to the active layer, and wherein each constituent layer of the second layer has a lower refractive index than the thickness-weighted-average of the refraction indices of the active layer. - View Dependent Claims (4, 6, 8, 9, 10, 12, 15)
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16. A light emitting device comprising:
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a substrate layer; a first layer which is disposed above the substrate layer, and which comprises at least one layer including a semiconductor cladding layer of a first conductivity type; an active layer disposed above the first layer; and a second layer which is disposed above the active layer, and which has a two-dimensional periodic structure in a surface thereof, the second layer comprising multiple layers including a semiconductor cladding layer of a second conductivity type and an intermediate layer having a refractive index that is less than or equal to a refractive index of the active layer and that is higher than a refractive index of any other constituent layer of the second layer. - View Dependent Claims (18, 20, 22, 24)
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17. A light emitting device comprising:
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a substrate layer; a first layer which comprises at least one layer and which is disposed above the substrate layer; an active layer which has a multiple quantum well structure and which is disposed above the first layer; and a second layer which is disposed above the active layer, and which has a two-dimensional periodic structure in a surface thereof, the second layer comprising multiple layers including an intermediate layer having a refractive index that is less than or equal to a refractive index of a well layer of the multiple quantum well structure and that is higher than a refractive index of any other constituent layer of the second layer. - View Dependent Claims (19, 21, 23, 25)
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Specification