Method of making thin film photovoltaic solar cell
AssigneeUniversity of Delaware
InventorAllen M. Barnett
Life of this patent
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Abstract
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.
Claims37
In a method of fabricating a thin film photovoltaic device, which includes as its components a substrate functioning as a support and as an opaque electrical contact, semiconductor layers functioning as an absorber-generator and as a collector-converter, and transparent electrical contact means, said method including depositing at least one semiconductor layer from a liquid saturated solution of a semiconductor material dissolved in a solvent, the improvement being the steps of:
- a. applying over the substrate a metallurgical barrier layer to prevent contamination of the liquid saturated solution and of the semiconductor layers by the substrate;
- b. continuously depositing over the metallurgical barrier layer a first semiconductor layer of a first selected conductivity type by moving the substrate through a liquid saturated solution of a first semiconductor material dissolved in a solvent and applying a gradient across the saturated solution to drive the growth of the first semiconductor layer.
In the method of claim I wherein the temperature of the saturated solution is essentially constant in time.
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 layer;
- (c) continuously depositing over the barrier layer a first semiconductor layer of a first selected conductivity type by moving the substrate through a liquid saturated solution of a first semiconductor material dissolved in a solvent and applying a temperature gradient across the saturated solution to drive the growth of the first semiconductor layer;
- (d) continuously depositing a second semiconductor layer having a conductivity type opposite the first selected conductivity type by moving the substrate through an additional liquid saturated solution of a second semiconductor material dissolved in a solvent and applying a temperature gradient across the second saturated solution to drive the growth of the second semiconductor layer.
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 optical reflection metallurgical barrier layer having a predetermined depth to provide for enhanced reflection of light;
- (c) continuously depositing over the optical reflection barrier layer a first semiconductor layer of a first selected conductivity type by moving the substrate through a liquid saturated solution of a first semiconductor material dissolved in a solvent and applying a temperature gradient across the saturated solution to drive the growth of the first semiconductor layer;
- (d) continuously depositing a second semiconductor layer having a conductivity type opposite the first selected conductivity type by moving the substrate through an additional liquid saturated solution of a second semiconductor material dissolved in a solvent and applying a temperature gradient across the second saturated solution to drive the growth of the second semiconductor layer.
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 layer;
- (c) continuously depositing over the optically transparent barrier layer a first semiconductor layer of a first selected conductivity type by moving the substrate through a liquid saturated solution of a first semiconductor material dissolved in a solvent and applying a temperature gradient across the saturated solution to drive the growth of the first semiconductor layer;
- (d) doping a layer of liquid saturated solution that remains on the deposited first semiconductor layer to provide a second semiconductor layer having conductivity type opposite to said first semiconductor layer.
Dependencies are inferred from the claim text.