EP0079790A2
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EP
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A thin film photovoltaic solar cell and method of making the same
Assignee: Individual
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Filing: 1982-11-15
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Granted: —
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Expires: 2002-11-15
Abstract
Abstract A thin film photovoltaic solar cell having an opaque electrical contact which consists of a low-cost substrate, such as a metal alloy or a metallurgical grade crystalline silicon and a barrier layer which is optically reflective, a first semiconductor layer, a second semiconductor layer, a transparent electrical contact and an encapsulant. Solar cell quality semiconductors are grown using a constant temperature sliding boat liquid phase process in a continuous or semi-continuous mode. The growth is driven by applying a temperature gradient or other gradient across the melt, with the substrate at a cooler temperature, after thermal equilibrium is obtained between the solution and the substrate. Growth occurs from the bottom of the solution to prevent contamination of the growth layers by extraneous particles in the solution.
Inventors
- 👤 Allen M. Barnett
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-10-30 22:34
CPC Classifications
H; H10; H10F; H10F71/00; H10F71/127; H10F71/121; H10F71/125; H10F71/1253; H10F77/00; H10F77/40; H10F77/42; H10F77/488; Y; Y02; Y02E; Y02E10/00; Y02E10/50; Y02E10/52; Y02E10/543; Y02E10/544; Y02E10/547; Y02P; Y02P70/00; Y02P70/50
Claims Analysis
Total Claims: 20
Claim 1
Independent Claim
70 words
A method of fabricating a thin film photovoltaic device on a substrate selected from the group consisting of metals, metal alloys and metallurgical grade semiconductors comprising the steps of (a) depositing over the substrate a semiconductor layer from a liquid saturated solution comprising a semiconductor material dissolved in a solvent, and (b) applying a temperature and/or electric gradient across the saturated solution to drive the growth of the semiconductor layer.
Claim 2
Independent Claim
70 words
A method of fabricating a thin film photovoltaic device on a substrate selected from the group consisting of metals, metal alloys and metallurgical grade semiconductors comprising the steps of (a) depositing over the substrate a semiconductor layer from a liquid saturated solution comprising a semiconductor material dissolved in a solvent, and (b) applying a temperature and/or electric gradient across the saturated solution to drive the growth of the semiconductor layer.
Claim 3
Dependent Claim
21 words
The method of claim 1 in which step (b) includes maintaining the substrate as the cooler end of a temperature gradient.
Claim 4
Dependent Claim
54 words
The method of claim 1 in which there is provided further steps of depositing an additional semiconductor layer from an additional liquid saturated solution comprising a semiconductor material dissolved in a solvent, and applying a temperature and/or electric gradient across the additional liquid saturated solution to drive the growth of the additional semiconductor layer.
Claim 5
Dependent Claim
22 words
The method of claim 3 in which the additional semiconductor layer is opposite in conductivity type from the first mentioned semiconductor layer.
Claim 6
Dependent Claim
56 words
The method of claim 4 in which the additional semiconductor layer is (1) the same material type as the first mentioned semiconductor layer and can be used to form a homojunction photovoltaic device or (2) different than the semiconductor material of the first mentioned semiconductor layer and can be used to form a heterojunction photovoltaic device.
Claim 7
Dependent Claim
64 words
The method of claim 1 in which there is provided further steps of adding a dopant to an additional layer of the liquid saturated solution applied on the first mentioned deposited semiconductor layer, and growing the doped layer to form a photovoltaic junction, and applying a gradient across the additional layer of liquid saturated solution to drive the growth of the additional doped layer.
Claim 8
Dependent Claim
55 words
In a method for fabricating a thin film photovoltaic device on a substrate chosen from the group consisting of metals, metal alloys and metallurgical grade semiconductors having semiconductor layers functioning as a collector, an absorber and a barrier layer, the improvement comprising the step of applying over the substrate an optically transparent metallurgical barrier layer.
Claim 9
Dependent Claim
55 words
In a method for fabricating a thin film photovoltaic device on a substrate chosen from the group consisting of metals, metal alloys and metallurgical grade semiconductors having semiconductor layers functioning as a collector, an absorber and a barrier layer, the improvement comprising the step of applying over the substrate an optically transparent metallurgical barrier layer.
Claim 10
Dependent Claim
87 words
In a thin film photovoltaic device on a substrate selected from the group consisting of metals, metal alloys and metallurgical grade semiconductors having semiconductor layers functioning as a collector and as an absorber and a barrier layer, the improvement comprising (a) a textured substrate surface to provide back surface reflection to increase performance of the device by increased photon absorption, (b) an optical reflection layer formed over the textured substrate, and (c) the substrate surface is textured to provide optimal internal reflection of light to said absorher.
Claim 11
Dependent Claim
87 words
In a thin film photovoltaic device on a substrate selected from the group consisting of metals, metal alloys and metallurgical grade semiconductors having semiconductor layers functioning as a collector and as an absorber and a barrier layer, the improvement comprising (a) a textured substrate surface to provide back surface reflection to increase performance of the device by increased photon absorption, (b) an optical reflection layer formed over the textured substrate, and (c) the substrate surface is textured to provide optimal internal reflection of light to said absorher.
Claim 12
Dependent Claim
52 words
The device of claim 8 in which said optical reflection layer has a predetermined depth to provide for reflection of light and said depth includes the distance defined as one-fourth of the wavelength of light to be reflected plus an integral number of wavelengths and said integral number of wavelengths includes zero.
Claim 13
Independent Claim
113 words
A method of fabricating a thin film photovoltaic device on a substrate selected from a group consisting of metals, metal alloys and metallurgical grade semiconductors comprising the steps of (a) depositing over the substrate a semiconductor layer from a liquid saturated solution comprising a semiconductor material dissolved in a solvent, (b) cooling the first saturated solution sufficiently to deposit a first semiconductor layer over the substrate, (c) cooling the second saturated solution sufficiently to deposit a second semiconductor layer from the second saturated solution over the first semiconductor layer, (d) heating both saturated solutions for about 5 to 15 minutes, and (e) thereafter repeating the foregoing sequence of steps starting with (a) above.
Claim 14
Independent Claim
113 words
A method of fabricating a thin film photovoltaic device on a substrate selected from a group consisting of metals, metal alloys and metallurgical grade semiconductors comprising the steps of (a) depositing over the substrate a semiconductor layer from a liquid saturated solution comprising a semiconductor material dissolved in a solvent, (b) cooling the first saturated solution sufficiently to deposit a first semiconductor layer over the substrate, (c) cooling the second saturated solution sufficiently to deposit a second semiconductor layer from the second saturated solution over the first semiconductor layer, (d) heating both saturated solutions for about 5 to 15 minutes, and (e) thereafter repeating the foregoing sequence of steps starting with (a) above.
Claim 15
Independent Claim
128 words
A method of fabricating a thin film photovoltaic device on a substrate selected from a group consisting of metals, metal alloys and metallurgical grade semiconductors comprising the steps of (a) texturing the substrate, (b) applying over the textured substrate an optically transparent, conducting metallurgical barrier, (c) depositing over the optically transparent layer a first semiconductor layer from a liquid saturated solution comprising a semiconductor material dissolved in a solvent, (d) applying a temperature gradient across the saturated solution to drive the growth of the first semiconductor layer, (e) depositing a second semiconductor layer from an additional liquid saturated solution comprising a semiconductor material dissolved in a solvent, and (f) applying a temperature gradient across the additional liquid saturated solution to drive the growth of the second semiconductor layer.
Claim 16
Independent Claim
128 words
A method of fabricating a thin film photovoltaic device on a substrate selected from a group consisting of metals, metal alloys and metallurgical grade semiconductors comprising the steps of (a) texturing the substrate, (b) applying over the textured substrate an optically transparent, conducting metallurgical barrier, (c) depositing over the optically transparent layer a first semiconductor layer from a liquid saturated solution comprising a semiconductor material dissolved in a solvent, (d) applying a temperature gradient across the saturated solution to drive the growth of the first semiconductor layer, (e) depositing a second semiconductor layer from an additional liquid saturated solution comprising a semiconductor material dissolved in a solvent, and (f) applying a temperature gradient across the additional liquid saturated solution to drive the growth of the second semiconductor layer.
Claim 17
Independent Claim
139 words
A method of fabricating a thin film photovoltaic device on a substrate selected from a group consisting of metals, metal alloys and metallurgical grades of semiconductor material comprising the steps of (a) texturing the substrate, (b) applying over the textured substrate an optically transparent layer having a predetermined depth to provide for reflection of light, (c) depositing over the optical reflection layer a first semiconductor layer from a liquid saturated solution comprising a semiconductor material dissolved in a molten metallic solvent, (d) applying a temperature gradient across the saturated solution to drive the growth of the first semiconductor layer, (e) depositing a second semiconductor layer from an additional liquid saturated solution comprising a material dissolved in a solvent, and (f) applying a temperature gradient across the additional liquid saturated solution to drive the growth of the second semiconductor layer.
Claim 18
Independent Claim
139 words
A method of fabricating a thin film photovoltaic device on a substrate selected from a group consisting of metals, metal alloys and metallurgical grades of semiconductor material comprising the steps of (a) texturing the substrate, (b) applying over the textured substrate an optically transparent layer having a predetermined depth to provide for reflection of light, (c) depositing over the optical reflection layer a first semiconductor layer from a liquid saturated solution comprising a semiconductor material dissolved in a molten metallic solvent, (d) applying a temperature gradient across the saturated solution to drive the growth of the first semiconductor layer, (e) depositing a second semiconductor layer from an additional liquid saturated solution comprising a material dissolved in a solvent, and (f) applying a temperature gradient across the additional liquid saturated solution to drive the growth of the second semiconductor layer.
Claim 19
Independent Claim
36 words
The method of claims 11 or 12 in which there is provided the further step of texture etching said second ,semiconductor layer to trap photons by causing multiple reflections until photons enter said second semiconductor layer.
Claim 20
Independent Claim
38 words
The method of claims 10, 11 or 12 in which said first and second semiconductors are chosen from the group consisting of silicon, copper sulfide, gallium arsenide, indium phosphide, zinc phosphide, cadmium sulfide, zinc-cadmium sulphide and cadmium telleride.
References Cited (Backward Citations)
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