Chemical surface deposition of ultra-thin semiconductors
OwnerBrian E. McCandless, William N. Shafarmaninventors
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Abstract
A chemical surface deposition process for forming an ultra-thin semiconducting film of Group IIB-VIA compounds onto a substrate. This process eliminates particulates formed by homogeneous reactions in bath, dramatically increases the utilization of Group IIB species, and results in the formation of a dense, adherent film for thin film solar cells. The process involves applying a pre-mixed liquid coating composition containing Group IIB and Group VIA ionic species onto a preheated substrate. Heat from the substrate causes a heterogeneous reaction between the Group IIB and VIA ionic species of the liquid coating composition, thus forming a solid reaction product film on the substrate surface.
Claims32
A process for forming a film on a substrate which comprises:
- a) forming a liquid coating composition which comprises at least one Group IIB ionic species, at least one Group VIA ionic species, and a complexing agent capable of causing the Group IIB ionic species and the Group VIA ionic species to combine;
- b) applying the liquid coating composition onto a heated substrate surface, which substrate surface is at a temperature higher than the temperature of the liquid coating composition;
- and
- c) causing the Group IIB ionic species and the Group VIA ionic species to react on the heated substrate surface under conditions sufficient to form a solid reaction product film comprising a reduced form of the Group IIB ionic species and the Group VIA ionic species on the substrate surface.
A process for forming a solar cell which comprises:
- a) forming a liquid coating composition which comprises at least one Group IIB ionic species, at least one Group VIA ionic species, and a complexing agent capable of causing the Group IIB ionic species and the Group VIA ionic species to combine;
- b) applying the liquid coating composition onto a heated substrate surface, which substrate surface is at a temperature higher than the temperature of the liquid coating composition;
- c) causing the Group IIB ionic species and the Group VIA ionic species to react on the heated substrate surface under conditions sufficient to form a solid reaction product film comprising a reduced form of the Group IIB ionic species and the Group VIA ionic species on the substrate surface;
- d) removing any excess liquid coating composition from the substrate;
- e) rinsing the film with water;
- and
- f) drying the film.
Dependencies are inferred from the claim text.