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US 2012/0055543 A1Published application
Back contact diffusion barrier layers for group ibiiiavia photovoltaic cells
AssigneeSoloPower, Inc.
InventorsMustafa Pinarbasi, James Freitag, Jorge Vasquez
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Abstract
The present invention provides for new ohmic contact materials and diffusion barriers for Group IBIIIAVIA based solar cell structures, which eliminate two way diffusion while preserving the efficient ohmic contacts between the substrate and the absorber layers.
Claims22
A method of manufacturing a Cu(In,Ga) Se2 thin-film solar cell, comprising:
- forming an intermediate layer on a surface of a flexible conductive substrate, the flexible conductive substrate including iron (Fe) species, the step of forming the intermediate layer comprising:
- forming a conductive barrier stack on the surface of the flexible conductive substrate, the conductive barrier stack including a chromium (Cr) film applied to the surface of the flexible conductive substrate and a titanium nitride (TiN) film deposited on the Cr film;
- depositing a contact layer on the conductive barrier stack;
- depositing a nucleation layer on the contact layer;
- depositing an absorber precursor including Cu species, In species, Ga species and Se species over the nucleation layer;
- applying heat to the absorber precursor to form therefrom an absorber layer including a Cu(In,Ga) Se2 thin film compound, wherein the step of forming the absorber layer causes some of the Fe species in the flexible substrate to diffuse towards the absorber layer and some of the Se species in the absorber layer to diffuse towards the flexible conductive substrate, and wherein the conductive barrier stack inhibits diffusion of both the iron (Fe) species and the Se species across the conductive barrier stack during the step of applying heat;
- disposing a transparent conductive layer on the thin film absorber layer, the transparent layer including a buffer layer deposited on the thin film absorber and a transparent conductive oxide layer formed on the buffer layer;
- forming a top terminal on the transparent conductive layer, thereby resulting in the Cu(In,Ga) Se2 thin-film solar cell;
- and
- wherein after the step of forming, the conductive barrier stack continues to inhibit diffusion of both the iron (Fe) species and the Se species across the conductive barrier stack.
7 more elements
A solar cell, comprising:
- a flexible conductive substrate including Fe species;
- a thin film absorber layer including Cu species, In species, Ga species and Se species formed over the flexible conductive substrate layer;
- an intermediate layer disposed between the flexible conductive substrate and the thin film absorber layer, the intermediate layer including:
- a conductive barrier stack on the surface of the flexible conductive substrate, the conductive barrier stack including a chromium (Cr) film applied to the surface of the flexible conductive substrate and a titanium nitride (TiN) film deposited on the Cr film, wherein the conductive barrier stack inhibits diffusion of both the iron (Fe) species from the flexible conductive substrate across the conductive barrier stack and the selenium Se species from the thin film absorber layer across the conductive barrier stack;
- a contact layer deposited on the conductive barrier stack;
- a nucleation layer deposited on the contact layer;
- a transparent layer deposited on the thin film absorber layer, the transparent layer including a buffer layer deposited on the thin film absorber and a transparent conductive oxide layer formed on the buffer layer;
- and
- a top terminal formed on the transparent layer.
6 more elements
Dependencies are inferred from the claim text.