Method and structure for eliminating edge peeling in thin-film photovoltaic absorber materials

Abstract

A method for manufacturing a thin-film photovoltaic device includes providing a glass substrate contained sodium species. The glass substrate comprising a surface region and a peripheral edge region surround the surface region. The method further includes forming a barrier material overlying the surface region and partially overlying the peripheral edge region and forming a conductor material overlying the barrier material. Additionally, the method includes forming at least a first trench in a vicinity of the peripheral edge region to remove substantially the conductor material therein and forming precursor materials overlying the patterned conductor material. Furthermore, the method includes thermally treating the precursor materials to transform the precursor materials into a film of photovoltaic absorber. The first trench is configured to maintain the film of photovoltaic absorber substantially free from peeling off the conductor material.

What is claimed is: 
     
         1 . A film structure for manufacturing a photovoltaic device free of peeling effect, the structure comprising:
 a glass substrate having a surface region and a bulk region, the bulk region comprising sodium species, the surface region being surrounded by a peripheral edge region;   a barrier material overlying the surface region and partially overlying the peripheral edge region;   a conductor material overlying the barrier material and partially overlying the peripheral edge region;   a first trench with the substantially all the conductor material therein being removed, the first trench being at least formed a closed loop in a vicinity of the peripheral edge region surrounding the surface region;   one or more thicknesses of precursor materials overlying the conductor material and at least partially filling the first trench, wherein the one or more thicknesses of precursor materials being subjected to an environment of reactive Selenium gaseous species at temperatures above 400° C. and transformed into a film of photovoltaic absorber, and the film of photovoltaic absorber is characterized by substantially free from peeling-off the conductor material anywhere within the surface region surrounded by the first trench.   
     
     
         2 . The film structure of  claim 1  wherein the glass substrate comprises a soda lime glass panel. 
     
     
         3 . The film structure of  claim 1  wherein the barrier material comprises a film material selected from silicon oxide, or silicon nitride, or silicon oxynitride, or aluminum-containing silicon oxide. 
     
     
         4 . The film structure of  claim 1  wherein the first trench is located about 4 mm or smaller away from the peripheral edge region of the glass substrate. 
     
     
         5 . The film structure of  claim 1  wherein the first trench comprises a width of about 90 μm and greater and a depth at least equal to a thickness of the conductor material. 
     
     
         6 . The film structure of  claim 1  wherein the first trench comprises a physical barrier to substantially block all sodium species diffusing from the peripheral edge region into the conductor material to induce film peeling in the interface between the conductor material and the film of photovoltaic absorber. 
     
     
         7 . The film structure of  claim 1  wherein the one or more thicknesses of precursor materials comprises a first thickness of sodium-bearing copper-gallium species, a second thickness of copper-gallium species, and a third thickness of indium species.