US4683160A
Expired / Lapsed
US
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Solar cells with correlated roughness substrate
Assignee: ExxonMobil Technology and Engineering Co
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Filing: 1985-05-09
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Granted: 1987-07-28
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Expires: 2005-05-09
Abstract
Abstract A thin film photoconductive device with a substrate structure of "correlated roughness" is disclosed for enhancing the absorption of solar light.
Inventors
- 👤 Aaron N. Bloch
- 👤 Ping Sheng
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-08 00:36
CPC Classifications
H; H10; H10F; H10F71/00; H10F71/10; H10F71/103; H10F77/00; H10F77/70; H10F77/703; Y; Y02; Y02E; Y02E10/00; Y02E10/50; Y02P; Y02P70/00; Y02P70/50; Y10; Y10T; Y10T428/00; Y10T428/24; Y10T428/24355; Y10T428/24479
Claims Analysis
Total Claims: 7
Claim 1
Independent Claim
96 words
A photoconductive device comprising an active layer of semiconductor material having a pair of opposed surfaces, one of said surfaces of said active layer textured with microstructures, said microstructures corresponding to the Fourier transform of the structure factor S(k), where S(k) has been chosen to maximize ##EQU6## where F(ω.sub.k)=I(ω.sub.k)A(ω.sub.k)S(k)N(ω.sub.k) F(ω k )=absorbed light intensity; I(ω k )=intensity of incident light; A(ω k )=absorption of light by the semiconductor; N(ω k )=density of guided mode state; ω k =frequency of guided mode of wave-vector k; ω 31 , ω + =limits of the frequency range of interest.
Claim 2
Dependent Claim
96 words
A photoconductive device comprising an active layer of semiconductor material having a pair of opposed surfaces, one of said surfaces of said active layer textured with microstructures, said microstructures corresponding to the Fourier transform of the structure factor S(k), where S(k) has been chosen to maximize ##EQU6## where F(ω.sub.k)=I(ω.sub.k)A(ω.sub.k)S(k)N(ω.sub.k) F(ω k )=absorbed light intensity; I(ω k )=intensity of incident light; A(ω k )=absorption of light by the semiconductor; N(ω k )=density of guided mode state; ω k =frequency of guided mode of wave-vector k; ω 31 , ω + =limits of the frequency range of interest.
Claim 3
Dependent Claim
47 words
The photoconductive device of claim 1 wherein said structure factor S(k) is given by ##EQU7## where ω k (m, θ)=angular frequency of m th guided mode; θ=angle of incidence of light measured from the vertical; m max =total number of allowed guided modes in the semiconductor layer.
Claim 4
Dependent Claim
86 words
The photoconductive device of claim 2 wherein said microstructures have mean diameters which increase in preselected increments between d min =2π/k max and d max =2π/k min where k max -k min is the half width of S(k) centered about its peak value of k o where S(k) has been evaluated for a preselected material and wavelength range, wherein the number of microstructures N(d) with mean diameter d is selected to the number of microstructures N(d o ) with mean diameter, d o , by ##EQU8##
Claim 5
Dependent Claim
13 words
The photoconductive device of claim 3 wherein said semiconductor material is amorphous silicon.
Claim 6
Dependent Claim
36 words
The photoconductive device of claim 4 wherein said layer of amorphous silicon has a thickness of 0.5 μm and said S(k) is evaluated between the wavelength range λ - =0.6 μm and λ + =0.08 μm.
Claim 7
Dependent Claim
26 words
The photoconductive device of claim 5 wherein the preseleced increment in the increase in mean diameter of said microstructures is between 0.05 μm and 0.025 μm.
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) | 1990-07-27 | 1991-01-26 | 1991-07-28 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1994-07-27 | 1995-01-26 | 1995-07-28 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1998-07-27 | 1999-01-26 | 1999-07-28 | $7700.00 | Window Closed / Lapsed |