Electrical field-assisted ultrafast doping in the polycrystalline cdte solar technology
AssigneeArizona Board of Regents on behalf of Arizona State University
InventorFeng YAN
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Abstract
Methods are disclosed for selectively doping grain boundaries in polycrystalline chalcogenide thin films for photovoltaic applications. In some embodiments, a chalcogenide-based or cadmium-based polycrystalline substrate is treated with a chloride-containing solution and contacted with an electrolyte comprising at least one dopant. An electric field is applied such that the dopant is selectively driven into grain-boundary regions while limiting dopant incorporation within grain interiors. In some embodiments, excess dopant material is removed from a surface of the substrate, followed by a thermal treatment to diffuse dopant material into grain interiors. The methods may be applied to CdTe or CdSeTe thin films and to group V dopants.
Claims20
A method of making a thin film for a solar cell, the method comprising:
- treating a chalcogenide-based polycrystalline substrate with a solution comprising a chloride compound;
- contacting the chalcogenide-based polycrystalline substrate with an electrolyte comprising at least one dopant;
- applying an electric field to the chalcogenide-based polycrystalline substrate such that the at least one dopant is selectively disposed in grain boundaries of the chalcogenide-based polycrystalline substrate, and
- heating the chalcogenide-based polycrystalline for a duration of from one second to one hour, thereby diffusing the at least one dopant from the grain boundaries to grain interiors of the chalcogenide-based polycrystalline substrate.
A method of making a thin film, the method comprising:
- treating a cadmium-based polycrystalline substrate with a solution comprising a chloride compound;
- contacting the cadmium-based polycrystalline substrate with an electrolyte comprising at least one dopant;
- applying an electric field to the cadmium-based polycrystalline substrate such that the at least one dopant is selectively disposed in grain boundaries of the cadmium-based polycrystalline substrate, and
- heating the cadmium-based polycrystalline substrate, thereby diffusing the at least one dopant from the grain boundaries to grain interiors of the cadmium-based polycrystalline substrate.
A method of selectively doping grain boundaries in a polycrystalline chalcogenide thin film, the method comprising:
- treating a polycrystalline chalcogenide substrate with a chloride-containing solution;
- contacting the polycrystalline chalcogenide substrate with an electrolyte comprising at least one dopant;
- applying an electric field across the polycrystalline chalcogenide substrate such that the at least one dopant is driven into grain-boundary regions of the polycrystalline chalcogenide substrate;
- and
- removing excess dopant material from a surface of the polycrystalline chalcogenide substrate.
Dependencies are inferred from the claim text.