Semiconductor light-emitting device
First Claim
1. A semiconductor light-emitting device comprising:
- a substrate; and
a plurality of III-V compound semiconductor layers supported by said substrate, each layer containing at least Ga and N as principal constituents, wherein said plurality of compound semiconductor layers include, sequentially arranged,a first cladding layer of a first conductivity type, said first cladding layer including a plurality AlxGa1-xN (0≦
x≦
1) layers in which x increases toward said substrate, each of said AlxGa1-xN layers having a respective refractive index,an active layer with a multi-quantum-well structure that includes at least two InGaN well layers, said first cladding layer being interposed between said substrate and said active layer, anda second cladding layer of a second conductivity type, opposite the first conductivity type and disposed on an opposite side of said active layer from said first cladding layer, said second cladding layer having a refractive index, wherein said light-emitting device has a light confinement coefficient in a range from 1.5% to 2.0%, the light confinement coefficient indicating proportion of light in said at least two InGaN well layers to overall waveguide light in said light-emitting device during light emission by said light-emitting device.
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Accused Products
Abstract
A semiconductor laser, having an active layer with a double-quantum-well structure, includes two InGaN well layers, each of which has a thickness of 5 nm. The threshold current deteriorates to a relatively small degree while differential efficiency is improved considerably in a region having a light confinement coefficient Γ of 3.0% or less. The light confinement coefficient indicates the proportion of light in the well layers with respect to light in the light emitting device, during light emission. When the light confinement coefficient Γ is less than 1.5%, the threshold current increases considerably and the improvement in differential efficiency becomes small. It is therefore preferable that the lower limit of the light confinement coefficient Γ be about 1.5%. A differential efficiency of 1.6 W/A or more is obtained when light the confinement coefficient Γ is 3.0% or less, and a differential efficiency of 1.7 W/A or more is obtained when the light confinement coefficient Γ is 2.6% or less.
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Citations
5 Claims
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1. A semiconductor light-emitting device comprising:
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a substrate; and a plurality of III-V compound semiconductor layers supported by said substrate, each layer containing at least Ga and N as principal constituents, wherein said plurality of compound semiconductor layers include, sequentially arranged, a first cladding layer of a first conductivity type, said first cladding layer including a plurality AlxGa1-xN (0≦
x≦
1) layers in which x increases toward said substrate, each of said AlxGa1-xN layers having a respective refractive index,an active layer with a multi-quantum-well structure that includes at least two InGaN well layers, said first cladding layer being interposed between said substrate and said active layer, and a second cladding layer of a second conductivity type, opposite the first conductivity type and disposed on an opposite side of said active layer from said first cladding layer, said second cladding layer having a refractive index, wherein said light-emitting device has a light confinement coefficient in a range from 1.5% to 2.0%, the light confinement coefficient indicating proportion of light in said at least two InGaN well layers to overall waveguide light in said light-emitting device during light emission by said light-emitting device. - View Dependent Claims (2, 3, 4, 5)
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Specification