US5242505A
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Amorphous silicon-based photovoltaic semiconductor materials free from Staebler-Wronski effects
Assignee: Electric Power Research Institute
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Filing: 1991-12-03
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Granted: 1993-09-07
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Expires: 2011-12-03
Abstract
Abstract Alloys of amorphous silicon with Group VIa elements are disclosed that form high-quality materials for photovoltaic cells that are resistant to Staebler-Wronski photodegradation. Also disclosed are methods for manufacturing the alloys. The alloys can be formed as films on solid-state substrates by reacting silane gas and at least one alloying gas (H2M, wherein M is an element from Group VIa of the periodic table), preferably with hydrogen dilution, by a glow-discharge method such as plasma-enhanced chemical vapor deposition. The alloys can have an optical bandgap energy from about 1.0 eV to about 2.3 eV, as determined by selecting one or more different Group VIa elements for alloying or by changing the concentration(s) of the alloying element(s) in the alloy. The alloys exhibit excellent light-to-dark conductivity ratios, excellent structural quality, and resistance to Staebler-Wronski degradation. They can be used as "i" type or doped for use as "p" or "n" type materials.
Inventors
- 👤 Guang H. Lin
- 👤 Mu Z. He
- 👤 Mridula Kapur
- 👤 John O'M. Bockris
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-05 10:28
CPC Classifications
H; H10; H10F; H10F10/00; H10F10/10; H10F10/17; H10F77/00; H10F77/10; H10F77/12; H10F77/127; H10F77/16; H10F77/169; H10F77/1692; Y; Y02; Y02E; Y02E10/00; Y02E10/50; Y02E10/548; Y10; Y10T; Y10T428/00; Y10T428/12; Y10T428/12493; Y10T428/12528
Claims Analysis
Total Claims: 31
Claim 1
Independent Claim
58 words
A composition of matter comprising: a solid-state alloy comprising amorphous silicon, hydrogen, and an alloying element selected from a group consisting of sulfur, selenium, and tellurium, the alloy having a photoconductivity that exhibits a change of less than one order of magnitude after the alloy is illuminated with white light for six hours at 100 mW/cm 2 .
Claim 2
Dependent Claim
58 words
A composition of matter comprising: a solid-state alloy comprising amorphous silicon, hydrogen, and an alloying element selected from a group consisting of sulfur, selenium, and tellurium, the alloy having a photoconductivity that exhibits a change of less than one order of magnitude after the alloy is illuminated with white light for six hours at 100 mW/cm 2 .
Claim 3
Dependent Claim
12 words
An alloy as recited in claim 1 layered on a solid-state substrate.
Claim 4
Dependent Claim
12 words
A photovoltaic cell comprised of an alloy as recited in claim 1.
Claim 5
Dependent Claim
32 words
A photovoltaic cell comprised of a p-doped semiconductor layer, an n-doped semiconductor layer, and an intrinsic layer, wherein at least one of said layers comprises an alloy as recited in claim 1.
Claim 6
Dependent Claim
21 words
A composition of matter as recited in claim 1 having a light-to-dark conductivity ratio of no less than 10 2 .
Claim 7
Dependent Claim
22 words
A composition of matter as recite din claim 1 having a concentration of hydrogen of no greater than about 10 at. %.
Claim 8
Dependent Claim
27 words
A composition of matter as recited in claim 1 wherein at least 90 percent of the hydrogen present in the alloy is in a Si-H bond form.
Claim 9
Dependent Claim
14 words
A composition of matter as recited in claim 1 further comprising an n-type dopant.
Claim 10
Dependent Claim
14 words
A composition of matter as recited in claim 1 further comprising a p-type dopant.
Claim 11
Dependent Claim
26 words
A composition of matter as recited in claim 1 exhibiting a B factor increase as the concentration of the alloying element is increased in the alloy.
Claim 12
Dependent Claim
27 words
A composition of matter as recited in claim 1 exhibiting a substantially constant refractive index as the concentration of the alloying element is increased in the alloy.
Claim 13
Dependent Claim
20 words
A composition of matter as recited in claim 1 exhibiting a void fraction of no greater than about three percent.
Claim 14
Dependent Claim
87 words
A solid-state composition of matter for use in photovoltaic cells, comprising a homogeneous alloy of hydrogenated amorphous silicon and an alloying element selected from a group consisting of sulfur, selenium, and tellurium, the alloy having (a) a photoconductivity that exhibits a change of less than one order of magnitude after the alloy is illuminated with white light for six hours at 100 mW/cm 2 ; (b) a light-to-dark conductivity ratio of not less than 10 2 ; and (c) a void fraction of less than three percent.
Claim 15
Dependent Claim
87 words
A solid-state composition of matter for use in photovoltaic cells, comprising a homogeneous alloy of hydrogenated amorphous silicon and an alloying element selected from a group consisting of sulfur, selenium, and tellurium, the alloy having (a) a photoconductivity that exhibits a change of less than one order of magnitude after the alloy is illuminated with white light for six hours at 100 mW/cm 2 ; (b) a light-to-dark conductivity ratio of not less than 10 2 ; and (c) a void fraction of less than three percent.
Claim 16
Dependent Claim
22 words
A material as recited in claim 13 having an optical bandgap energy within a range of about 1.0 to about 2.3 eV.
Claim 17
Dependent Claim
28 words
A composition of matter as recited in claim 13 wherein the alloying element is present in the alloy at a concentration of up to about 30 at. %.
Claim 18
Dependent Claim
14 words
A composition of matter as recited in claim 5 layered on a solid-state substrate.
Claim 19
Dependent Claim
12 words
A photovoltaic cell comprised of a material as recited in claim 13.
Claim 20
Dependent Claim
99 words
A solid-state material for use in photovoltaic cells, comprising an alloy of amorphous silicon, hydrogen, and an alloying element selected from a group consisting of sulfur, selenium, and tellurium, the material having (a) a photoconductivity that exhibits a change of less than one order of magnitude after the material is illuminated with white light for six hours at 100 mW/cm 2 ; (b) a light-to-dark conductivity ratio of not less than 10 2 ; (c) a concentration of hydrogen of less than 10 at. %; and (d) at least 90 percent of the hydrogen in an Si--H bond form.
Claim 21
Dependent Claim
99 words
A solid-state material for use in photovoltaic cells, comprising an alloy of amorphous silicon, hydrogen, and an alloying element selected from a group consisting of sulfur, selenium, and tellurium, the material having (a) a photoconductivity that exhibits a change of less than one order of magnitude after the material is illuminated with white light for six hours at 100 mW/cm 2 ; (b) a light-to-dark conductivity ratio of not less than 10 2 ; (c) a concentration of hydrogen of less than 10 at. %; and (d) at least 90 percent of the hydrogen in an Si--H bond form.
Claim 22
Dependent Claim
23 words
A material as recited in claim 18 layered on a solid-state substrate selected from a group consisting of silicon, glass, quartz, and titanium.
Claim 23
Dependent Claim
12 words
A photovoltaic cell comprised of a material as recited in claim 18.
Claim 24
Independent Claim
134 words
A method for preparing a solid-state material for use in photovoltaic cells, comprising the steps of: (a) providing a solid-state substrate; (b) providing reactive gases individually comprising silane gas, hydrogen gas, and an alloying gas selected from a group consisting of H 2 M compounds wherein M is an element from a group consisting of sulfur, selenium, and tellurium; (c) providing an energy source sufficient to cause the reactive gases to react with each other and form a solid-state alloy of silicon, hydrogen, and M on the substrate; and (d) introducing the reactive gases to the energy source and the substrate so as to cause the reactive gases to react and form, on the substrate, a hydrogenated amorphous alloy of silicon and M, thereby forming a solid-state semiconductor material for use in photovoltaic cells.
Claim 25
Independent Claim
134 words
A method for preparing a solid-state material for use in photovoltaic cells, comprising the steps of: (a) providing a solid-state substrate; (b) providing reactive gases individually comprising silane gas, hydrogen gas, and an alloying gas selected from a group consisting of H 2 M compounds wherein M is an element from a group consisting of sulfur, selenium, and tellurium; (c) providing an energy source sufficient to cause the reactive gases to react with each other and form a solid-state alloy of silicon, hydrogen, and M on the substrate; and (d) introducing the reactive gases to the energy source and the substrate so as to cause the reactive gases to react and form, on the substrate, a hydrogenated amorphous alloy of silicon and M, thereby forming a solid-state semiconductor material for use in photovoltaic cells.
Claim 26
Dependent Claim
15 words
A method as recited in claim 21 wherein the energy source comprises an rf plasma.
Claim 27
Dependent Claim
18 words
A method as recited in claim 21 wherein the energy source further comprises heat applied to the substrate.
Claim 28
Dependent Claim
26 words
A method as recited in claim 23 wherein the substrate is heated to a temperature within a range of about 230° C. to about 360° C.
Claim 29
Dependent Claim
24 words
A method as recited in claim 24 wherein the substrate is heated at a subatmospheric pressure of about 230 mTorr to about 1800 mTorr.
Claim 30
Dependent Claim
36 words
A method as recited in claim 21 wherein, in step (d), the alloy of hydrogenated amorphous silicon and M is formed on the surface of the substrate at a rate no greater than about 1 Å/s.
Claim 31
Dependent Claim
13 words
A solid-state semiconductor material prepared by a method as recited in claim 21.
References Cited (Backward Citations)
JPS561579A
Cited
JPS561578A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1996-09-06 | 1997-03-08 | 1997-09-07 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2000-09-06 | 2001-03-08 | 2001-09-07 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2004-09-06 | 2005-03-08 | 2005-09-07 | $7700.00 | Window Closed / Lapsed |