Pressure transfer process for thin film solar cell fabrication

Abstract

In one aspect, a method for fabricating a thin film solar cell includes the following steps. A first absorber material is deposited as a layer A on a substrate while applying pressure to the substrate/layer A. A second absorber material is deposited as a layer B on layer A while applying pressure to the substrate/layer B. A third absorber material is deposited as a layer C on layer B while applying pressure to the substrate/layer C. A fourth absorber material is deposited as a layer D on layer C while applying pressure to the substrate/layer D. The first absorber material comprises copper, the second absorber material comprises indium, the third absorber material comprises gallium, and the fourth absorber material comprises one or more of sulfur and selenium, and wherein by way of performing the steps of claim 1 a chalcogenide absorber layer is formed on the substrate.

What is claimed is: 
     
         1 . An apparatus for fabricating a thin film solar cell, the apparatus comprising:
 a set of rollers (a) configured to, when a substrate passes between the set of rollers (a), deposit a first absorber material as a layer A on the substrate while applying pressure to both the substrate and the layer A;   a set of rollers (b) configured to, when the substrate with the layer A thereon passes through the set of rollers (b), deposit a second absorber material as a layer B on the layer A while applying pressure to both the substrate and the layer B;   a set of rollers (c) configured to, when the substrate with the layers A and B thereon passes through the set of rollers (c), deposit a third absorber material as a layer C on the layer B while applying pressure to both the substrate and the layer C;   a set of rollers (d) configured to, when the substrate with the layers A-C thereon passes through the set of rollers (d), deposit a fourth absorber material as a layer D on the layer C while applying pressure to both the substrate and the layer D; and   a set of rollers (e) configured to, when the substrate with the layers A-D thereon passes through the set of rollers (e), anneal the layers A-D while applying pressure to both the substrate and the layer D,   wherein the first absorber material comprises copper, the second absorber material comprises indium, the third absorber material comprises gallium, and the fourth absorber material comprises one or more of sulfur and selenium, and wherein the apparatus is configured to form a chalcogenide absorber layer on the substrate.   
     
     
         2 . The apparatus of  claim 1 , further comprising:
 a set of rollers (f) configured to, when the substrate with the layers A-C thereon passes through the set of rollers (f), soft anneal the layers A-C while applying pressure to both the substrate and the layer C.   
     
     
         3 . The apparatus of  claim 1 , wherein the set of rollers (a) are configured to deposit the layer A from a chemical or electrochemical solution, the apparatus further comprising:
 a set of rollers (g) which following deposition of the first absorber material on the substrate is configured to, when the substrate with the layer A thereon passes through the set of rollers (g), heat the layer A while applying pressure to both the substrate and the layer A.   
     
     
         4 . The apparatus of  claim 1 , wherein the set of rollers (b) are configured to deposit the layer B from a chemical or electrochemical solution, the apparatus further comprising:
 a set of rollers (h) which following deposition of the layer B on the layer A is configured to, when the substrate with the layers A and B thereon passes through the set of rollers (h), heat the layer B while applying pressure to both the substrate and the layer B.   
     
     
         5 . The apparatus of  claim 1 , wherein the set of rollers (b) are configured to deposit the layer B from a molten bath, the apparatus further comprising:
 a set of rollers (h) which following deposition of the layer B on the layer A is configured to, when the substrate with the layers A and B thereon passes through the set of rollers (h), cool the layer B while applying pressure to both the substrate and the layer B.   
     
     
         6 . The apparatus of  claim 1 , wherein the set of rollers (c) are configured to deposit the layer C from a chemical or electrochemical solution, the apparatus further comprising:
 a set of rollers (i) which following deposition of the layer C on the layer B is configured to, when the substrate with the layers A-C thereon passes through the set of rollers (i), heat the layer C while applying pressure to both the substrate and the layer C.   
     
     
         7 . The apparatus of  claim 1 , wherein the set of rollers (c) are configured to deposit the layer C from a molten bath, the apparatus further comprising:
 a set of rollers (i) which following deposition of the layer C on the layer B is configured to, when the substrate with the layers A-C thereon passes through the set of rollers (i), cool the layer C while applying pressure to both the substrate and the layer C.   
     
     
         8 . The apparatus of  claim 1 , wherein the set of rollers (d) are configured to deposit the layer D from a chemical or electrochemical solution, the apparatus further comprising:
 a set of rollers G) which following deposition of the layer D on the layer C is configured to, when the substrate with the layers A-D thereon passes through the set of rollers G), heat the layer D while applying pressure to both the substrate and the layer D.   
     
     
         9 . The apparatus of  claim 1 , wherein the set of rollers (d) are configured to deposit the layer D from a molten bath, the apparatus further comprising:
 a set of rollers G) which following deposition of the layer D on the layer C is configured to, when the substrate with the layers A-D thereon passes through the set of rollers G), cool the layer D while applying pressure to both the substrate and the layer D.