Multiple wavelength light emitting device
First Claim
1. A multiple wavelength light emitting device having a single p-n junction and at least two light emitting layers within a minority carrier diffusion region comprising:
- a p-type Ga1-X1 AlX1 As layer;
a p-type Ga1-X2 AlX2 As layer;
a p-type Ga1-X3 AlX3 As layer; and
an n-type Ga1-Y AlY As layer,where X1, X2, X3 and Y represent aluminum arsenide mixed crystal ratios of the respective layers, wherein said aluminum arsenide mixed crystal ratios of the respective layers satisfy the following expression;
space="preserve" listing-type="equation">Y>
X.sub.3 >
X.sub.2
space="preserve" listing-type="equation">and
space="preserve" listing-type="equation">X.sub.1>
X.sub.3.
1 Assignment
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Accused Products
Abstract
A multiple wavelength light emitting device having a single p-n junction and at least two light emitting layers within a diffusion region of a minority carrier comprises a p-type Ga1-x1 Alx1 As layer, a p-type Ga1-x2 Alx2 As layer, a p-type Ga1-x3 Alx3 As layer, and an n-type Ga1-y Aly As layer, where x1, x2, x3 and Y represent aluminum arsenide mixed crystal ratios of the respective layers. The light emitting alyers, i.e., the p-type Ga1-x2 Alx2 As layer and the p-type Ga1-x3 Alx3 As layer each have a different band gap to emit an infrared light and a visible light, respectively. Since the infrared and ivsible lights are simultaneously emitted, emission of the infrared light can be confirmed or monitored by the visible light. The light emitting device of the present invention utilizes an energy well for trapping electrons and an energy barrier for preventing electrons from diffusing to improve the whole light emitting efficiency.
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Citations
9 Claims
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1. A multiple wavelength light emitting device having a single p-n junction and at least two light emitting layers within a minority carrier diffusion region comprising:
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a p-type Ga1-X1 AlX1 As layer; a p-type Ga1-X2 AlX2 As layer; a p-type Ga1-X3 AlX3 As layer; and an n-type Ga1-Y AlY As layer, where X1, X2, X3 and Y represent aluminum arsenide mixed crystal ratios of the respective layers, wherein said aluminum arsenide mixed crystal ratios of the respective layers satisfy the following expression;
space="preserve" listing-type="equation">Y>
X.sub.3 >
X.sub.2
space="preserve" listing-type="equation">and
space="preserve" listing-type="equation">X.sub.1>
X.sub.3.
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2. A multiple wavelength light emitting device having a single p-n junction and at least two light emitting layers within a minority carrier diffusion region comprising:
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a p-type Ga1-X1 AlX1 As layer; a p-type Ga1-X2 AlX2 As layer; a p-type Ga1-X3 AlX3 As layer; and an n-type Ga1-Y AlY As layer, where X1, X2, X3 and Y represent aluminum arsenide mixed crystal ratios of the respective layers, wherein said aluminum arsenide mixed crystal ratios of the respective layers satisfy the following expressions;
space="preserve" listing-type="equation">Y>
X.sub.2 >
X.sub.3
space="preserve" listing-type="equation">and
space="preserve" listing-type="equation">X.sub.1 >
X.sub.2.
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3. A multiple wavelength light emitting device having a single p-n junction and at least two light emitting layers within a minority carrier diffusion region comprising:
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a p-type Ga1-X1 AlX1 As layer; a p-type Ga1-X2 AlX2 As layer; a p-type Ga1-X3 AlX3 As layer; and an n-type Ga1-Y AlY As layer, where X1, X2, X3 and Y represent aluminum arsenide mixed crystal ratios of the respective layers, wherein said p-type Ga1-X2 AlX2 As layer and said p-type Ga1-X3 AlX3 As layer are light emitting layers, respectively, having a different band gap.
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4. A multiple wavelength light emitting device having a single p-n junction and at least two light emitting layers within a minority carrier diffusion region comprising:
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a p-type Ga1-X1 AlX1 As layer; a p-type Ga1-X2 AlX2 As layer; a p-type Ga1-X3 AlX3 As layer; and an n-type Ga1-Y AlY As layer, where X1, X2, X3 and Y represent aluminum arsenide mixed crystal ratios of the respective layers, wherein said p-type Ga1-X1 AlX1 As layer has a higher band gap than both said p-type Ga1-X2 AlX2 As layer and said p-type Ga1-X3 AlX3 As layer to form a high potential barrier.
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5. A multiple wavelength light emitting device having a single p-n junction comprising:
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at least two p-type light emitting layers respectively having a different band gap within a minority carrier diffusion region; a p-type layer adjacent to one end surface of said light emitting layers; and an n-type layer adjacent to the other end surface of said light emitting layers. - View Dependent Claims (6, 7, 8)
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9. A multiple light emitting device having a single p-n junction manufactured by a process comprising the steps of:
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preparing a GaAs mono-crystal substrate; epitaxially growing a p-type Ga1-X3 AlX1 As layer, a p-type Ga1-X2 AlX2 As layer, a p-type Ga1-X3 AlX3 As layer and an n-type Ga1-Y AlY As layer sequentially on said GaAs mono-crystal substrate; and removing said GaAs mono-crystal substrate after said epitaxial growth step has been completed.
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Specification