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US3636471A
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Method of and apparatus for enhancing radiation from indirect-gap semiconductors
Assignee: Massachusetts Institute of Technology
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Filing: 1969-07-03
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Granted: 1972-01-18
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Expires: 1989-07-03
Abstract
Abstract Apparatus is disclosed for injecting phonons of appropriate frequency and intensity into the luminescent regions of an indirect-gap semiconductor to enhance luminescence therein. If the luminescent region is an optical resonant cavity in which an inverted population of the electric energy levels or bands of the semiconductor exists, the injected phonons can function to initiate and/or enhance lasing action in the region.
Inventors
- 👤 Robert H Rediker
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-26 22:55
CPC Classifications
H; H01; H01S; H01S5/00; H01S5/30; H01S5/32
Claims Analysis
Total Claims: 20
Claim 1
Independent Claim
30 words
A method as claimed in claim 1 in which the charge carriers are at least one of electrons and holes and the excess is established by forward biasing the semiconductor.
Claim 2
Dependent Claim
29 words
A method as claimed in claim 1 in which the charge carriers are at least one of electrons and holes and the excess is established by electron beam pumping.
Claim 3
Dependent Claim
28 words
A method as claimed in claim 1 in which the charge carriers are at least one of electrons and holes and the excess is established by optical pumping.
Claim 4
Independent Claim
75 words
A method of enhancing luminescence of an indirect-gap semiconductor, that comprises, directing pumping energy to the semiconductor to effect luminescence in the active part thereof, and injecting phonons of appropriate frequency and intensity into said active part to enhance the probability of radiative recombination across the indirect gap of charge carriers therein, the appropriate frequency of the phonons being that which is required to take up the crystal momentum change of the recombining charge carriers.
Claim 5
Dependent Claim
76 words
A method as claimed in claim 5 in which the pumping energy is sufficiently great to establish an inverted population of the electronic energy levels or bands in an indirect-gap semiconductor having an optical resonant cavity which includes at least a portion of said active part, the phonons being effective to enhance the probability of radiative recombination of the charge carriers from the energy levels or bands to effect lasing and to enhance any existing lasing.
Claim 6
Dependent Claim
34 words
A method as claimed in claim 5 in which a tunnel-diode junction is provided in the semiconductor and an electric potential is impressed across the junction to provide an electric current and said phonons.
Claim 7
Independent Claim
110 words
A method of initiating and enhancing lasing action of an indirect-gap semiconductor, that comprises, establishing an inverted population of at least one of the electronic energy levels and bands in an indirect-gap semiconductor forming at least part of an optical resonant cavity, and injecting phonons of appropriate frequency and intensity into the optical cavity to enhance radiative recombination across the indirect gap of the electrons from the inverted population levels and bands to initiate said lasing and to enhance any existing lasing, said appropriate frequency of the phonons being that which is required to take up the crystal momentum change of the recombining electrons from the energy levels or bands.
Claim 8
Dependent Claim
34 words
A method as claimed in claim 8 in which a tunnel-diode junction is provided in the semiconductor, and an electric potential is impressed across the junction to provide an electric current and said phonons.
Claim 9
Dependent Claim
36 words
A method as claimed in claim 8 in which the inverted population is stored in the semiconductor and in which lasing is triggered by a burst of said phonons, thereby to provide high-peak power laser output.
Claim 10
Dependent Claim
17 words
A method as claimed in claim 8 in which the inverted population is effected by optical pumping.
Claim 11
Dependent Claim
19 words
A method as claimed in claim 8 in which the inverted population is effected by forward biasing a diode.
Claim 12
Dependent Claim
18 words
A method as claimed in claim 8 in which the inverted population is effected by electron beam pumping.
Claim 13
Independent Claim
61 words
A method of enhancing luminescence of a semiconductor, that comprises, injecting phonons of appropriate frequency and intensity into the luminescent region of the semiconductor to enhance the probability for radiative recombination of at least one of electrons and holes therein, said appropriate frequency being that which is required to take up any crystal momentum change of the recombining electrons and holes.
Claim 14
Dependent Claim
94 words
A semiconductor laser that comprises a diode laser structure of an indirect-gap semiconducting material forming at least part of an optical resonant cavity, means for establishing an inverted population of the electronic energy levels or bands of the semiconductor, and means for injecting phonons of the appropriate frequency and intensity to enhance radiative recombination across the indirect gap of the electrons from the inverted population levels or bands to provide lasing action, said appropriate frequency of the phonons being that which is required to take up the crystal momentum change of the recombining electrons.
Claim 15
Dependent Claim
35 words
A semiconductor laser as claimed in claim 15 in which the semiconductor is silicon and the frequency is about 1.4 X 1013 Hz. for optical phonons and about 4.4 X 1012 Hz. for acoustic phonons.
Claim 16
Dependent Claim
38 words
A semiconductor laser as claimed in claim 15 in which the phonon injection means comprises a tunnel-junction region in the semiconductor structure and having an electric potential impressed thereacross to produce both an electric current and said phonons.
Claim 17
Dependent Claim
28 words
A semiconductor laser as claimed in claim 15 in which the inverted population is established by forward biasing the semiconductor at the semiconductor junction at which lasing occurs.
Claim 18
Dependent Claim
84 words
An indirect-gap semiconductor adapted to luminesce, that comprises, means for establishing an excess of charge carriers in the luminescent region of the semiconductor and means for enhancing the probability of recombination of the charge carriers across the indirect gap of the semiconductor, said means for enhancing comprising means for generating and injecting phonons of appropriate frequency and intensity into said region, said appropriate frequency of the phonons being that which is required to take up the crystal momentum change of the recombining charge carriers.
Claim 19
Dependent Claim
65 words
An indirect-gap semiconductor as claimed in claim 19 in which the means for generating and injecting phonons includes a tunnel junction which is formed as part of the semiconductor and of the same semiconductor material as the luminescent region to provide a band structure in the tunnel junction that corresponds to the band structure in the luminescent region thereby to furnish phonons of appropriate frequency.
Claim 20
Dependent Claim
46 words
An indirect-gap semiconductor as claimed in claim 20 that further includes a source of electric potential connected across the tunnel junction to produce both the phonons and an electric current, the intensity of the phonons thereby produced being determined by the magnitude of the electric current.
References Cited (Backward Citations)
No citation records indexed.
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1975-01-17 | 1975-07-19 | 1976-01-18 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1979-01-17 | 1979-07-19 | 1980-01-18 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1983-01-17 | 1983-07-19 | 1984-01-18 | $7700.00 | Window Closed / Lapsed |