US5068867A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Coupled quantum well strained superlattice structure and optically bistable semiconductor laser incorporating the same
Assignee: Raytheon Co
•
Filing: 1989-11-20
•
Granted: 1991-11-26
•
Expires: 2009-11-20
Abstract
Abstract A short-period, strained superlattice structure includes two coupled quantum well layers separated by a barrier layer. The quantum well layers are preferably formed of indium arsenide and are 2 monolayers thick. The barrier layer is preferably formed of gallium arsenide and is 2 to 10 monolayers thick. The quantum well layers have a lattice parameter or constant which is sufficiently different from that of the barrier layer that a permanent strain exists in the surface. The layers are sufficiently thin that they remain in an unrelaxed state, thereby precluding the formation of misfit dislocations. As an alternative, the superlattice structure may include more than two quantum well layers, each adjacent two of which are separated by a barrier layer. As another alternative, a plurality of structures, each including two quantum well layers separated by a barrier laser may be provided, with each structure separated by a gallium arsenide buffer layer on the order of 170 to 204 angstroms thick. Where incorporated into a semiconductor diode layer as an active region, the strained superlattice structure is capable of exhibiting optical bistability.
Inventors
- 👤 Thomas C. Hasenberg
- 👤 William J. Gignac
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-29 18:39
CPC Classifications
H; H10; H10H; H10H20/00; H10H20/80; H10H20/81; H10H20/811; H10H20/812; B; B82; B82Y; B82Y20/00; G; G02; G02F; G02F3/00; G02F3/02; G02F3/026; H01; H01S; H01S5/00; H01S5/30; H01S5/34; H01S5/3403; H01S5/3425; H01S5/343; H01S5/34313
Claims Analysis
Total Claims: 37
Claim 1
Independent Claim
82 words
A strained superlattice structure comprising: a plurality of coupled quantum well layers; and a barrier layer formed between each two adjacent quantum well layers respectively; the quantum well layers having a bandgap energy which is lower than the bandgap energy of the barrier layer; the quantum well layers having a lattice parameter which is selected to be different from the lattice parameter of the barrier layer such that a permanent strain is created in the quantum well layers and the barrier layer.
Claim 2
Dependent Claim
82 words
A strained superlattice structure comprising: a plurality of coupled quantum well layers; and a barrier layer formed between each two adjacent quantum well layers respectively; the quantum well layers having a bandgap energy which is lower than the bandgap energy of the barrier layer; the quantum well layers having a lattice parameter which is selected to be different from the lattice parameter of the barrier layer such that a permanent strain is created in the quantum well layers and the barrier layer.
Claim 3
Dependent Claim
101 words
A strained superlattice structure comprising: a plurality of coupled quantum well layers; and a barrier layer formed between each two adjacent quantum well layers respectively; the quantum well layers having a bandgap energy which is lower than the bandgap energy of the barrier layer; the quantum well layers having a lattice parameter which is selected to be different from the lattice parameter of the barrier layer such that a permanent strain is created in the quantum well layers and the barrier layer; wherein the lattice parameter of the quantum well layers is higher than the lattice parameter of the barrier layer.
Claim 4
Dependent Claim
101 words
A strained superlattice structure comprising: a plurality of coupled quantum well layers; and a barrier layer formed between each two adjacent quantum well layers respectively; the quantum well layers having a bandgap energy which is lower than the bandgap energy of the barrier layer; the quantum well layers having a lattice parameter which is selected to be different from the lattice parameter of the barrier layer such that a permanent strain is created in the quantum well layers and the barrier layer; wherein the lattice parameter of the quantum well layers is higher than the lattice parameter of the barrier layer.
Claim 5
Dependent Claim
50 words
A superlattice structure as in claim 1, in which the quantum well layers and the barrier layer have thicknesses selected such that the quantum well layers and barrier layer remain in an unrelaxed state, thereby precluding formation of misfit dislocations therein, and tunneling will occur between adjacent quantum well layers.
Claim 6
Dependent Claim
23 words
A superlattice structure as in claim 1, in which the quantum well layers comprise indium arsenide and the barrier layer comprises gallium arsenide.
Claim 7
Dependent Claim
28 words
A superlattice structure as in claim 4, in which the quantum well layers are 2 monolayers thick and the barrier layer is between 2 and 10 monolayers thick.
Claim 8
Dependent Claim
17 words
A superlattice structure as in claim 5, in which the barrier layer is substantially 5 monolayers thick.
Claim 9
Dependent Claim
16 words
A superlattice structure as in claim 1, comprising two quantum well layers and one barrier layer.
Claim 10
Dependent Claim
145 words
A superlattice structure comprising: a plurality of quantum well structures and a buffer layer formed between each two adjacent quantum well structures; each quantum well structure comprising two quantum well layers and a barrier layer formed between the quantum well layers; the quantum well layers having a bandgap energy which is lower than the bandgap energy of the barrier layer and the buffer layer; the quantum well layers having a lattice parameter which is selected to be different from the lattice parameters of the barrier layer and the buffer layer such that a permanent strain is created in the superlattice structure; the quantum well layers, barrier layer and buffer layer having thicknesses selected such that the quantum well layers, barrier layer and buffer layer remain in an unrelaxed state, thereby precluding formation of misfit dislocations therein, and tunneling will occur between adjacent quantum well layers.
Claim 11
Dependent Claim
145 words
A superlattice structure comprising: a plurality of quantum well structures and a buffer layer formed between each two adjacent quantum well structures; each quantum well structure comprising two quantum well layers and a barrier layer formed between the quantum well layers; the quantum well layers having a bandgap energy which is lower than the bandgap energy of the barrier layer and the buffer layer; the quantum well layers having a lattice parameter which is selected to be different from the lattice parameters of the barrier layer and the buffer layer such that a permanent strain is created in the superlattice structure; the quantum well layers, barrier layer and buffer layer having thicknesses selected such that the quantum well layers, barrier layer and buffer layer remain in an unrelaxed state, thereby precluding formation of misfit dislocations therein, and tunneling will occur between adjacent quantum well layers.
Claim 12
Dependent Claim
26 words
A superlattice structure as in claim 8, in which the quantum well layers comprise indium arsenide, and the barrier layer and buffer layer comprise gallium arsenide.
Claim 13
Dependent Claim
38 words
A superlattice structure as in claim 9, in which the quantum well layers are 2 monolayers thick, the barrier layer is between 2 and 10 monolayers thick, and the buffer layer is between 170 and 204 angstroms thick.
Claim 14
Dependent Claim
130 words
An optically bistable semiconductor laser including an active region, confinement means for creating an optical waveguide effect in the active region, electrode means for applying a bias voltage to the active region, and a substrate for supporting the active region, confinement means and electrode means, the active region comprising: a plurality of coupled quantum well layers; and a barrier layer formed between each two adjacent quantum well layers respectively; the quantum well layers having a bandgap energy which is lower than the bandgap energy of the barrier layer; the quantum well layers having a lattice parameter which is selected to be different from the lattice parameter of the barrier layer such that a permanent strain is created in the quantum well layers and the barrier layer which causes optical bistability.
Claim 15
Dependent Claim
130 words
An optically bistable semiconductor laser including an active region, confinement means for creating an optical waveguide effect in the active region, electrode means for applying a bias voltage to the active region, and a substrate for supporting the active region, confinement means and electrode means, the active region comprising: a plurality of coupled quantum well layers; and a barrier layer formed between each two adjacent quantum well layers respectively; the quantum well layers having a bandgap energy which is lower than the bandgap energy of the barrier layer; the quantum well layers having a lattice parameter which is selected to be different from the lattice parameter of the barrier layer such that a permanent strain is created in the quantum well layers and the barrier layer which causes optical bistability.
Claim 16
Dependent Claim
139 words
An optically bistable semiconductor laser, comprising: an active area which includes: a plurality of coupled quantum well layers; and a barrier layer formed between each two adjacent quantum well layers respectively; the quantum well layers having a bandgap energy which is lower than the bandgap energy of the barrier layer; the quantum well layers having a lattice parameter which is selected to be different from the lattice parameter of the barrier layer such that a permanent strain is created in the quantum well layers and the barrier layer which causes optical bistability; first and second optical and charge confinement layers which sandwich the active region therebetween; first and second electrode layers formed over the first and second confinement layers respectively; and a substrate for supporting the active area, first and second confinement layers, and first and second electrode layers.
Claim 17
Dependent Claim
139 words
An optically bistable semiconductor laser, comprising: an active area which includes: a plurality of coupled quantum well layers; and a barrier layer formed between each two adjacent quantum well layers respectively; the quantum well layers having a bandgap energy which is lower than the bandgap energy of the barrier layer; the quantum well layers having a lattice parameter which is selected to be different from the lattice parameter of the barrier layer such that a permanent strain is created in the quantum well layers and the barrier layer which causes optical bistability; first and second optical and charge confinement layers which sandwich the active region therebetween; first and second electrode layers formed over the first and second confinement layers respectively; and a substrate for supporting the active area, first and second confinement layers, and first and second electrode layers.
Claim 18
Dependent Claim
23 words
A semiconductor laser as in claim 12, in which the first and second confinement layers are doped with P-type and N-type impurities respectively.
Claim 19
Dependent Claim
22 words
A semiconductor laser as in claim 12, in which the first and second electrode layers are substantially coextensive with the active region.
Claim 20
Dependent Claim
23 words
A semiconductor laser as in claim 12, in which the substrate is formed between the first confinement layer and the first electrode layer.
Claim 21
Dependent Claim
149 words
An optically bistable a semiconductor laser including an active region, confinement means for creating an optical waveguide effect in the active region, electrode means for applying a bias voltage to the active region, and a substrate for supporting the active region, confinement means and electrode means, the active region comprising: a plurality of coupled quantum well layers; and a barrier layer formed between each two adjacent quantum well layers respectively; the quantum well layers having a bandgap energy which is lower than the bandgap energy of the barrier layer; the quantum well layers having a lattice parameter which is selected to be different from the lattice parameter of the barrier layer such that a permanent strain is created in the quantum well layers and the barrier layer which causes optical bistability; the lattice parameter of the quantum well layers being higher than the lattice parameter of the barrier layer.
Claim 22
Dependent Claim
149 words
An optically bistable a semiconductor laser including an active region, confinement means for creating an optical waveguide effect in the active region, electrode means for applying a bias voltage to the active region, and a substrate for supporting the active region, confinement means and electrode means, the active region comprising: a plurality of coupled quantum well layers; and a barrier layer formed between each two adjacent quantum well layers respectively; the quantum well layers having a bandgap energy which is lower than the bandgap energy of the barrier layer; the quantum well layers having a lattice parameter which is selected to be different from the lattice parameter of the barrier layer such that a permanent strain is created in the quantum well layers and the barrier layer which causes optical bistability; the lattice parameter of the quantum well layers being higher than the lattice parameter of the barrier layer.
Claim 23
Dependent Claim
51 words
A semiconductor laser as in claim 11, in which the quantum well layers and the barrier layer have thickness selected such that the quantum well layers and the barrier layer remain in an unrelaxed state, thereby precluding formation of misfit dislocations therein, and tunneling will occur between adjacent quantum well layers.
Claim 24
Dependent Claim
23 words
A semiconductor laser as in claim 11, in which the quantum well layers comprise indium arsenide and the barrier layer comprises gallium arsenide.
Claim 25
Dependent Claim
28 words
A semiconductor laser as in claim 18, in which the quantum well layers are 2 monolayers thick and the barrier layer is between 2 and 10 monolayers thick.
Claim 26
Dependent Claim
17 words
A semiconductor laser as in claim 19, in which the barrier layer is substantially 5 monolayers thick.
Claim 27
Dependent Claim
195 words
An optically bistable semiconductor laser including an active region, confinement means for creating an optical waveguide effect in the active region, electrode means for applying a bias voltage to the active region, and a substrate for supporting the active region, confinement means and electrode means, the active region comprising: a plurality of quantum well structures and a buffer layer formed between each two adjacent quantum well structures respectively; each quantum well structure comprising two quantum well layers and a barrier layer formed between the quantum well layers; the quantum well layers having a bandgap energy which is lower than the bandgap energy of the barrier layer and the buffer layer; the quantum well layers having a lattice parameter which is selected to be different from the lattice parameters of the barrier layer and the buffer layer such that a permanent strain is created in the active region which causes optical bistability; the quantum well layers, barrier layer and buffer layer having thicknesses selected such that the quantum well layers, barrier layer and buffer layer remain in an unrelaxed state, thereby precluding formation of misfit dislocations therein, and tunneling will occur between adjacent quantum well layers.
Claim 28
Dependent Claim
195 words
An optically bistable semiconductor laser including an active region, confinement means for creating an optical waveguide effect in the active region, electrode means for applying a bias voltage to the active region, and a substrate for supporting the active region, confinement means and electrode means, the active region comprising: a plurality of quantum well structures and a buffer layer formed between each two adjacent quantum well structures respectively; each quantum well structure comprising two quantum well layers and a barrier layer formed between the quantum well layers; the quantum well layers having a bandgap energy which is lower than the bandgap energy of the barrier layer and the buffer layer; the quantum well layers having a lattice parameter which is selected to be different from the lattice parameters of the barrier layer and the buffer layer such that a permanent strain is created in the active region which causes optical bistability; the quantum well layers, barrier layer and buffer layer having thicknesses selected such that the quantum well layers, barrier layer and buffer layer remain in an unrelaxed state, thereby precluding formation of misfit dislocations therein, and tunneling will occur between adjacent quantum well layers.
Claim 29
Dependent Claim
23 words
A semiconductor laser as in claim 21, in which the quantum well layers comprise indium arsenide, and the barrier layer comprises gallium arsenide.
Claim 30
Dependent Claim
28 words
A semiconductor laser as in claim 22, in which the quantum well layers are 2 monolayers thick, and the barrier layer is between 2 and 10 monolayers thick.
Claim 31
Dependent Claim
23 words
A semiconductor laser as in claim 23, in which the buffer layer comprises gallium arsenide and is between 170 and 204 angstroms thick.
Claim 32
Dependent Claim
46 words
A semiconductor laser as in claim 21, in which: the confinement means comprises first and second optical and charge confinement layers which sandwich the active region therebetween; and the electrode means comprises first and second electrode layers formed on the first and second confinement layers respectively.
Claim 33
Dependent Claim
23 words
A semiconductor laser as in claim 25, in which the first and second confinement layers are doped with P-type and N-type impurities respectively.
Claim 34
Dependent Claim
22 words
A semiconductor laser as in claim 25, in which the first and second electrode layers are substantially coextensive with the active region.
Claim 35
Dependent Claim
21 words
A semiconductor laser as in claim 25, further comprising a substrate formed between the first confinement layer and the active region.
Claim 36
Dependent Claim
117 words
An optically bistable semiconductor laser including an active region, confinement means for creating an optical waveguide effect in the active region, electrode means for applying a bias voltage to the active region, and a substrate for supporting the active region, confinement means and electrode means, the active region comprising: a plurality of coupled quantum well layers; and a barrier layer formed between each two adjacent quantum well layers respectively; the quantum well layers having a bandgap energy which is lower than the bandgap energy of the barrier layer; the quantum well layers and the barrier layer having thicknesses selected such that the quantum well layers are interactively coupled, and tunneling will occur between adjacent quantum well layers.
Claim 37
Dependent Claim
117 words
An optically bistable semiconductor laser including an active region, confinement means for creating an optical waveguide effect in the active region, electrode means for applying a bias voltage to the active region, and a substrate for supporting the active region, confinement means and electrode means, the active region comprising: a plurality of coupled quantum well layers; and a barrier layer formed between each two adjacent quantum well layers respectively; the quantum well layers having a bandgap energy which is lower than the bandgap energy of the barrier layer; the quantum well layers and the barrier layer having thicknesses selected such that the quantum well layers are interactively coupled, and tunneling will occur between adjacent quantum well layers.
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) | 1994-11-25 | 1995-05-27 | 1995-11-26 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1998-11-25 | 1999-05-27 | 1999-11-26 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2002-11-25 | 2003-05-27 | 2003-11-26 | $7700.00 | Window Closed / Lapsed |