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US3758875A
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Double heterostructure junction lasers
Assignee: AT&T Inc
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Filing: 1970-05-01
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Granted: 1973-09-11
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Expires: 1990-05-01
Abstract
Abstract A light emitting heterostructure diode includes a multilayered structure having a common conductivity type heterojunction and a p-n junction separated therefrom by a distance less than the diffusion length of minority carriers, thereby defining an intermediate region bounded by said junctions. In a single heterostructure (SH) diode there is one such heterojunction separating narrow and wide band gap regions of the same conductivity type and the p-n junction is a p-n homojunction formed in one instance by the diffusion of impurities into the narrow band gap region. When provided with an appropriate resonator, a confinement effect produced by an energy step (at the heterojunction) in the conduction band permits the SH diode to lase at higher temperatures and lower thresholds than heretofore possible, radiative electron-hole recombination occurring between the conduction and valence bands. In a double heterostructure (DH) the diode is provided with a second heterojunction positioned on the side of the p-n junction remote from the other heterojunction, or positioned coincident with the p-n junction, thereby defining an intermediate region between a pair of heterojunctions. When provided with an appropriate resonator the DH diode exhibits lower thresholds at higher temperatures than even the aforementioned SH diode. In both diodes additional improvement in the threshold occurs if the diode is provided with deep impurity levels of deep band tails. Without a resonator, both the SH and DH diodes function as electroluminescent diodes with radiation being emitted from the intermediate region through the wide band gap region, thereby advantageously resulting in lower absorption losses and higher efficiency. Dome-like configurations of the wide band gap region of this diode are also disclosed.
Inventors
- 👤 I Hayashi
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-24 09:19
CPC Classifications
H; H01; H01S; H01S5/00; H01S5/10; H01S5/18; H01S5/183; H01S5/18386; H01S5/18388; H10; H10H; H10H20/00; H10H20/80; H10H20/81; H10H20/811; H10H20/822; H10H20/824; H10P; H10P14/00; H10P14/20; H10P14/36; H01S5/30; H01S5/32; H01S5/323; H01S5/32308; H01S5/32316; Y; Y10; Y10S; Y10S148/00; Y10S148/065; Y10S148/067; Y10S148/072; Y10S148/107
Claims Analysis
Total Claims: 11
Claim 1
Independent Claim
166 words
In a double heterostructure junction laser, a semiconductor active medium comprising a common conductivity type first heterojunction, a p-n junction separated therefrom by a distance d1 which is less than the diffusion length of minority carriers injected toward said first heterojunction when said p-n junction is forward biased, a second heterojunction disposed on the side of said p-n junction remote from said first heterojunction and separated from said p-n junction by a distance d2 > OR = 0 which is less than the diffusion length of minority carriers injected toward said second heterojunction when said p-n junction is forward biased, thereby defining an intermediate region between said heterojunctions, the thickness t of said intermediate region being less than approximately 1.0 Mu and greater than approximately lambda /2 so that said laser is capable of continuous wave operation at temperatures at least as high as room temperature, where lambda is the wavelength of coherent radiation generated in said intermediate region when said p-n junction is forward biased.
Claim 2
Dependent Claim
166 words
In a double heterostructure junction laser, a semiconductor active medium comprising a common conductivity type first heterojunction, a p-n junction separated therefrom by a distance d1 which is less than the diffusion length of minority carriers injected toward said first heterojunction when said p-n junction is forward biased, a second heterojunction disposed on the side of said p-n junction remote from said first heterojunction and separated from said p-n junction by a distance d2 > OR = 0 which is less than the diffusion length of minority carriers injected toward said second heterojunction when said p-n junction is forward biased, thereby defining an intermediate region between said heterojunctions, the thickness t of said intermediate region being less than approximately 1.0 Mu and greater than approximately lambda /2 so that said laser is capable of continuous wave operation at temperatures at least as high as room temperature, where lambda is the wavelength of coherent radiation generated in said intermediate region when said p-n junction is forward biased.
Claim 3
Dependent Claim
130 words
A double heterostructure laser device having a current threshold for lasing and capable of continouus wave operation at temperatures at least as high as room temperature, comprising at least two reflecting surfaces forming an optical cavity resonator for sustaining coherent radiation, means for extracting a portion of the radiation from said resonator, an active medium according to claim 1 disposed between said surfaces and on the optic axis of said resonator, means for causing the injection of minority carriers across said p-n junction and toward said heterojunctions, thereby to produce radiative recombination of holes and electrons, said injection means comprising means for forward biasing said p-n junction and for applying direct current thereto in magnitude sufficient to produce optical radiation, and wherein said applied current exceeds said threshold for lasing.
Claim 4
Dependent Claim
25 words
The device of claim 1 wherein 0 <d2, said second heterojunction is a common conductivity type heterojunction and said p-n junction is a p-n homojunction.
Claim 5
Dependent Claim
22 words
The device of claim 1 wherein d2 0 and said second heterojunction and said p-n junction coincide to form a p-n heterojunction.
Claim 6
Dependent Claim
41 words
The device of claim 4 wherein said heterojunctions define a three-layered structure comprising a first layer of n-AlxGa1 xAs, said intermediate region of p-AlyGa1 yAs and a second layer of p-AlzGa1 zAs, where 0 < or = y <x and z.
Claim 7
Dependent Claim
22 words
The device of claim 44 Wherein the thickness t of said intermediate region is in the range of approximately 0.125-1.0 Mu .
Claim 8
Dependent Claim
33 words
The device of claim 44 in combination with a layer of p-GaAs formed on said second layer, thereby to permit the making of good electrical contact to said second layer and said diode.
Claim 9
Dependent Claim
185 words
For use in a double heterostructure injection laser, an active medium comprising a substrate comprising n-GaAs, a first wide band gap layer comprising n-AlxGa1 xAs, x > 0, contiguous with said substrate, an intermediate layer comprising p-GaAs contiguous with said first layer, thereby forming a p-n heterojunction at the interface between said layers, a second wide band gap layer comprising p-AlzGa1 zAs, z > 0, contiguous with said intermediate layer, thereby forming a p-p heterojunction at the interface between said intermediate and second layers, the separation of said heterojunctions being within the range of approximately 0.125 Mu -1.0 Mu , so that said laser is capable of continouus wave operation at temperatures at least as high as room temperature, a layer of p-GaAs contiguous with said second layer to permit the making of electrical contact thereto, a pair of oppositely facing reflecting surfaces formed transverse to said intermediate layer, thereby forming an optical cavity resonator for sustaining coherent radiation, means for extracting a portion of the radiation from said resonator, and at least one heat sink thermally coupled to said laser for extracting heat therefrom.
Claim 10
Dependent Claim
185 words
For use in a double heterostructure injection laser, an active medium comprising a substrate comprising n-GaAs, a first wide band gap layer comprising n-AlxGa1 xAs, x > 0, contiguous with said substrate, an intermediate layer comprising p-GaAs contiguous with said first layer, thereby forming a p-n heterojunction at the interface between said layers, a second wide band gap layer comprising p-AlzGa1 zAs, z > 0, contiguous with said intermediate layer, thereby forming a p-p heterojunction at the interface between said intermediate and second layers, the separation of said heterojunctions being within the range of approximately 0.125 Mu -1.0 Mu , so that said laser is capable of continouus wave operation at temperatures at least as high as room temperature, a layer of p-GaAs contiguous with said second layer to permit the making of electrical contact thereto, a pair of oppositely facing reflecting surfaces formed transverse to said intermediate layer, thereby forming an optical cavity resonator for sustaining coherent radiation, means for extracting a portion of the radiation from said resonator, and at least one heat sink thermally coupled to said laser for extracting heat therefrom.
Claim 11
Dependent Claim
52 words
The medium of claim 8 in combination with means for causing the injection of electrons across said p-n heterojunction, thereby to produce radiative recombination in said intermediate layer, said injection means comprising means for forward biasing said p-n heterojunction and for applying direct current thereto in magnitude sufficient to produce coherent radiation.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1976-09-10 | 1977-03-12 | 1977-09-11 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1980-09-10 | 1981-03-12 | 1981-09-11 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1984-09-10 | 1985-03-12 | 1985-09-11 | $7700.00 | Window Closed / Lapsed |