US4547622A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Solar cells and photodetectors
Assignee: Massachusetts Institute of Technology
•
Filing: 1984-04-27
•
Granted: 1985-10-15
•
Expires: 2004-04-27
Abstract
Abstract An improved photovoltaic device in which a charge separation junction is provided over a charge confining heterojunction. The charge separation junction is a junction formed of an n + -doped direct bandgap layer on a p-doped direct bandgap active layer. The charge confining heterojunction is formed by the interface of the active layer with a Back Surface Layer (BSL) of higher bandgap material than the active layer to provide a Back Surface Field (BSF). The percentage of Al in the layers may vary from Y=O to x≦0.42. The structure applies to both crystalline and amorphous material.
Inventors
- 👤 John C. C. Fan
- 👤 Ronald P. Gale
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-23 05:12
CPC Classifications
H; H10; H10F; H10F10/00; H10F10/10; H10F10/14; H10F10/144; H10F10/16; H10F10/163; Y; Y02; Y02E; Y02E10/00; Y02E10/50; Y02E10/544
Claims Analysis
Total Claims: 13
Claim 1
Independent Claim
80 words
A photovoltaic device with a back surface field (BSF) comprising: (a) a BSL layer of p-doped direct bandgap semiconductor material; (b) an active layer, formed on said BSL layer, of p-doped direct bandgap semiconductor material having an energy gap Eg less than that of the BSL layer and forming a heterojunction with said BSL layer; (c) a shallow layer less than 0.15 μm in thickness of n-doped direct bandgap semiconductor material forming a charge separation junction with the active layer.
Claim 2
Dependent Claim
80 words
A photovoltaic device with a back surface field (BSF) comprising: (a) a BSL layer of p-doped direct bandgap semiconductor material; (b) an active layer, formed on said BSL layer, of p-doped direct bandgap semiconductor material having an energy gap Eg less than that of the BSL layer and forming a heterojunction with said BSL layer; (c) a shallow layer less than 0.15 μm in thickness of n-doped direct bandgap semiconductor material forming a charge separation junction with the active layer.
Claim 3
Dependent Claim
23 words
The device of claim 1 in which the lattice mismatch between the BSL layer and the active layer is less than about 0.1%.
Claim 4
Dependent Claim
22 words
The device of claim 1 in which the semiconductor material of the BSL layer is Al x Ga 1-x As wherein 0.05≦x≦0.42.
Claim 5
Dependent Claim
20 words
The device of claim 3 in which the thickness "t" of the active layer is about 1 to 5 μm.
Claim 6
Dependent Claim
22 words
The device of claim 1 in which the energy gap Eg of the BSL layer is equal to or less than 2.
Claim 7
Dependent Claim
20 words
The device of claim 1 including a second cell affixed to the BSL layer to form a tandem cell structure.
Claim 8
Dependent Claim
19 words
The device of claim 1 including an optical reflector formed adjacent an exposed planar surface of the BSL layer.
Claim 9
Dependent Claim
16 words
The device of claim 1 in which AlGaAs is the material used in all the layers.
Claim 10
Dependent Claim
12 words
The device of claim 1 in which the layer material is amorphous.
Claim 11
Dependent Claim
78 words
A photovoltaic device with a back surface field (BSF) comprising: (a) a BSL layer of p + -doped direct bandgap Al x Ga 1-x As material; (b) an active layer of p-doped direct bandgap semiconductor Al y Ga 1-y As material forming a heterojunction with said BSL layer; (c) a layer of n + -doped direct bandgap Al y Ga 1-y As material forming a charge separation homojunction with the active layer and wherein x≦0.42, x-y>0.05 and y≧0.
Claim 12
Dependent Claim
78 words
A photovoltaic device with a back surface field (BSF) comprising: (a) a BSL layer of p + -doped direct bandgap Al x Ga 1-x As material; (b) an active layer of p-doped direct bandgap semiconductor Al y Ga 1-y As material forming a heterojunction with said BSL layer; (c) a layer of n + -doped direct bandgap Al y Ga 1-y As material forming a charge separation homojunction with the active layer and wherein x≦0.42, x-y>0.05 and y≧0.
Claim 13
Dependent Claim
23 words
The device of claim 10 in which the lattice mismatch between the BSL layer and the active layer is less than about 0.1%.
References Cited (Backward Citations)
US3675026A
Cited
US3982265A
Cited
US4227941A
Cited
US4416052A
Cited
US4427841A
Cited
US4442310A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1988-10-14 | 1989-04-15 | 1989-10-15 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1992-10-14 | 1993-04-15 | 1993-10-15 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1996-10-14 | 1997-04-15 | 1997-10-15 | $7700.00 | Window Closed / Lapsed |