US5128728A
Expired / Lapsed
US
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Semiconductor superlattice infrared source
Assignee: National Research Council Canada
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Filing: 1990-08-16
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Granted: 1992-07-07
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Expires: 2010-08-16
Abstract
Abstract An infrared emitting semiconductor device having a layer-shaped infrared emitting region with a superlattice structure. The superlattice structure consists of thin alternating narrow and wide wells separated by thin barriers. The narrow well has one quasibound state E' 0 while the wide well has two states E 0 anad E 1 with E' 0 being located between E 0 and E 1 . Under proper bias, an electron in state E 0 can resonately tunnel out of the well through the quasibound state E' 0 to the first excited state E 1 of the next wide well. This electron can then relax to the ground state E 0 where it can resonately tunnel to the next wide well and repeat the process. Infrared radiation with its photon energy equal to E 1 -E 0 is emitted as the electrons relax from E 1 to E 0 in the wide wells.
Inventors
- 👤 Hui C. Liu
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-01 11:04
CPC Classifications
H; H10; H10H; H10H20/00; H10H20/80; H10H20/81; H10H20/811; H10H20/812; B; B82; B82Y; B82Y20/00; H01; H01S; H01S5/00; H01S5/30; H01S5/34; H01S5/3401; H01S5/3402; H01S5/3418; H01S5/3419
Claims Analysis
Total Claims: 17
Claim 1
Independent Claim
139 words
A semiconductor device which can emit infrared radiation in the mid-to far-infrared range comprising an active semiconductor region consisting of alternating thin layers of substantially undoped semiconductive material forming a superlattice structure wherein the structure consists of alternating narrow and wide wells separated by thin barriers, the narrow wells having a width w' and wide wells a width w and designed such that the narrow wells have only one quasibound state E' 0 and the wide wells have two states E 0 and E 1 under 0 bias, whereby, under a suitable dc bias, electrons in state E 0 can resonately tunnel out of the well through the quasibound state E 0 to the first excited E 1 of the wide well where it can relax to the ground state E 0 , emitting infrared radiation in the process.
Claim 2
Dependent Claim
139 words
A semiconductor device which can emit infrared radiation in the mid-to far-infrared range comprising an active semiconductor region consisting of alternating thin layers of substantially undoped semiconductive material forming a superlattice structure wherein the structure consists of alternating narrow and wide wells separated by thin barriers, the narrow wells having a width w' and wide wells a width w and designed such that the narrow wells have only one quasibound state E' 0 and the wide wells have two states E 0 and E 1 under 0 bias, whereby, under a suitable dc bias, electrons in state E 0 can resonately tunnel out of the well through the quasibound state E 0 to the first excited E 1 of the wide well where it can relax to the ground state E 0 , emitting infrared radiation in the process.
Claim 3
Dependent Claim
22 words
A semiconductor device claimed in claim 1, wherein the superlattice structure is formed of Al x Ga 1-x As-GaAs material with x≦1.
Claim 4
Dependent Claim
38 words
A semiconductor device as claimed in claim 1, wherein the barrier layers have a width b where b has a width such that the tunneling time between two adjacent wide wells is faster than the radiative relaxation time.
Claim 5
Dependent Claim
16 words
A semiconductor device as claimed in claim 2, wherein the aluminium fraction x is about 0.45.
Claim 6
Dependent Claim
31 words
A semiconductor device as claimed in claim 1, wherein the first and last layer of the superlattice structure are in contact with heavily N-type doped semiconductor material which forms contact layers.
Claim 7
Dependent Claim
38 words
A semiconductor device as claimed in claim 2, wherein the barrier layers have a width b where b has a width such that the tunneling time between two adjacent wide wells is faster than the radiative relaxation time.
Claim 8
Dependent Claim
34 words
A semiconductor device as claimed in claim 2, wherein the width w is about 82 Å, the width w' is about 40 Å and the width of the barrier layers is about 15 Å.
Claim 9
Dependent Claim
33 words
A semiconductor device as claimed in claim 4, wherein the width w is about 82 Å, the width w' is about 40 Åand the width of the barrier layers is about 15 Å.
Claim 10
Dependent Claim
31 words
A semiconductor device as claimed in claim 2, wherein the first and last layer of the superlattice structure are in contact with heavily N-type doped semiconductor material which forms contact layers.
Claim 11
Dependent Claim
31 words
A semiconductor device as claimed in claim 4, wherein the first and last layer of the superlattice structure are in contact with heavily N-type doped semiconductor material which forms contact layers.
Claim 12
Dependent Claim
174 words
A semiconductor device comprising a superlattice structure comprising a plurality of relatively narrow layers and a plurality of relatively wide layers of substantially undoped semiconductor material, the narrow and wide layers being arranged alternately and being separated by thin barrier layers, wherein each wide layer provides a quantum well having two intersubband states having energy levels E 0 and E 1 , and each narrow layer provides a quantum well having only one state having an energy level E' 0 which is approximately equal to (E 0 +E 1 )/2, the arrangement being such that under bias of the device electrons resonantly tunnel through the barrier layers from a narrow layer to the energy level E 1 in an adjacent wide layer and from the energy level E 0 in a wide layer to an adjacent narrow layer, and in the wide layers electrons relax from the energy level E 1 to the energy level E 0 with emission of infrared radiation having a wavelength in a range of about 2 to 10 μm.
Claim 13
Dependent Claim
174 words
A semiconductor device comprising a superlattice structure comprising a plurality of relatively narrow layers and a plurality of relatively wide layers of substantially undoped semiconductor material, the narrow and wide layers being arranged alternately and being separated by thin barrier layers, wherein each wide layer provides a quantum well having two intersubband states having energy levels E 0 and E 1 , and each narrow layer provides a quantum well having only one state having an energy level E' 0 which is approximately equal to (E 0 +E 1 )/2, the arrangement being such that under bias of the device electrons resonantly tunnel through the barrier layers from a narrow layer to the energy level E 1 in an adjacent wide layer and from the energy level E 0 in a wide layer to an adjacent narrow layer, and in the wide layers electrons relax from the energy level E 1 to the energy level E 0 with emission of infrared radiation having a wavelength in a range of about 2 to 10 μm.
Claim 14
Dependent Claim
15 words
A semiconductor device as claimed in claim 11 wherein the superlattice structure comprises AlGaAs-GaAs material.
Claim 15
Dependent Claim
40 words
A semiconductor device as claimed in claim 12 wherein each wide layer has a width of about 82 Å, each narrow layer has a width of about 40 Å, and each barrier layer has a width of about 15 Å.
Claim 16
Dependent Claim
25 words
A semiconductor device as claimed in claim 13 and including contact areas of heavily N-typed doped semiconductor material between which the superlattice structure is arranged.
Claim 17
Dependent Claim
25 words
A semiconductor device as claimed in claim 11 and including contact areas of heavily N-type doped semiconductor material between which the superlattice structure is arranged.
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1995-07-07 | 1996-01-06 | 1996-07-07 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1999-07-07 | 2000-01-06 | 2000-07-07 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2003-07-07 | 2004-01-06 | 2004-07-07 | $7700.00 | Window Closed / Lapsed |