Photovoltaic device conducting layer

Abstract

A multilayered structure may include a doped buffer layer on a transparent conductive oxide layer.

1 . A multilayered structure comprising:
 a barrier layer adjacent to a substrate;   a transparent conductive oxide layer adjacent to the barrier layer; and   a buffer layer comprising a dopant adjacent to the transparent conductive oxide layer.   
     
     
         2 . The multilayered structure of  claim 1 , wherein the dopant is selected from the group consisting of copper, arsenic, and antimony. 
     
     
         3 . The multilayered structure of  claim 1 , wherein the doped buffer layer comprises a material selected from the group consisting of tin oxide, zinc oxide, zinc stannate, zinc magnesium oxide, and tin silicon oxide. 
     
     
         4 . The multilayered structure of  claim 1 , wherein the doped buffer layer comprises multiple layers. 
     
     
         5 . The multilayered structure of  claim 4 , wherein one of the multiple layers comprises a doped layer, and another one of the multiple layers is an undoped layer, and the doped layer is adjacent to the undoped layer. 
     
     
         6 . The multilayered structure of  claim 1 , wherein the doped buffer layer has a dopant concentration of more than about 1×10 15 /cm 2 . 
     
     
         7 . The multilayered structure of  claim 1 , wherein the doped buffer layer comprises a tin oxide and has a dopant to tin oxide ratio of about 10 −5  to about 10 −1 . 
     
     
         8 . The multilayered structure of  claim 1 , further comprising a semiconductor window layer adjacent to the doped buffer layer, wherein the semiconductor window layer comprises a material selected from the group consisting of cadmium sulfide, zinc sulfide, cadmium zinc sulfide, and zinc magnesium oxide. 
     
     
         9 . The multilayered structure of  claim 8 , further comprising a semiconductor absorber layer adjacent to the doped buffer layer, wherein the semiconductor absorber layer comprises a material selected from the group consisting of cadmium telluride, zinc telluride, and cadmium zinc telluride. 
     
     
         10 . The multilayered structure of  claim 9 , wherein the multilayered structure has a carrier concentration of greater than about 1×10 14 /cm 3 . 
     
     
         11 . A method of manufacturing a multilayered structure, the method comprising:
 forming a doped buffer layer adjacent to a transparent conductive oxide layer, wherein the transparent conductive oxide layer is adjacent to a substrate; and   forming a semiconductor window layer adjacent to the buffer layer;   forming a semiconductor absorber layer adjacent to the semiconductor window layer; and   and heating the multilayered structure to a temperature sufficient to diffuse dopant from the buffer layer into the semiconductor absorber layer.   
     
     
         12 . The method of  claim 11 , wherein the step of heating the multilayered structure comprises heating the multilayered structure to a temperature greater than 300 degrees C. 
     
     
         13 . The method of  claim 11 , wherein the step of heating the multilayered structure comprises heating the multilayered structure to a temperature greater than 450 degrees C. 
     
     
         14 . The method of  claim 11 , wherein the step of heating the multilayered structure comprises heating the multilayered structure to a temperature greater than 600 degrees C. 
     
     
         15 . The method of  claim 11 , wherein the step of heating the multilayered structure comprises heating the multilayered structure to a temperature greater than 750 degrees C. 
     
     
         16 . The method of  claim 11 , wherein the dopant comprises a material selected from the group consisting of copper, arsenic, and antimony. 
     
     
         17 . The method of  claim 11 , further comprising forming the transparent conductive oxide layer adjacent to the substrate before forming the doped buffer layer. 
     
     
         18 . The method of  claim 11 , wherein the step of forming a doped buffer layer comprises co-sputtering buffer layer material and dopant from separate sputter targets. 
     
     
         19 . The method of  claim 14 , wherein the buffer layer material comprises tin and the dopant comprises a material selected from the group consisting of copper, arsenic, and antimony. 
     
     
         20 . The method of  claim 11 , wherein the step of forming a doped buffer layer comprises forming a buffer layer adjacent to the transparent conductive oxide layer and doping the buffer layer with a dopant. 
     
     
         21 . The method of  claim 11 , wherein the doped buffer layer has more than about 1×10 15 /cm 2  of dopant. 
     
     
         22 . The method of  claim 11 , wherein the step of forming a doped buffer layer comprises a reactive sputtering process. 
     
     
         23 . The method of  claim 11 , wherein the step of forming a doped buffer layer comprises atmospheric pressure chemical vapor deposition. 
     
     
         24 . The method of  claim 11 , further comprising an additional step of heating the transparent conductive oxide stack comprising the transparent conductive oxide layer to anneal the transparent conductive oxide stack. 
     
     
         25 . A photovoltaic device comprising
 a barrier layer adjacent to a substrate;   a transparent conductive oxide layer adjacent to the barrier layer;   a buffer layer comprising a dopant adjacent to the transparent conductive oxide layer;   a semiconductor window layer adjacent to the buffer layer;   a semiconductor absorber layer adjacent to the semiconductor window layer, wherein the semiconductor absorber layer comprises a portion of the dopant, diffused from the buffer layer; and   a back contact adjacent to the semiconductor absorber layer.   
     
     
         26 . The photovoltaic device of  claim 25 , wherein the dopant comprises a material selected from the group consisting of copper, arsenic, and antimony. 
     
     
         27 . The photovoltaic device of  claim 25 , wherein the dopant diffused from the buffer layer to the semiconductor absorber layer is present in a substantially uniform concentration proximate to the buffer layer. 
     
     
         28 . A sputter target comprising:
 a sputter material comprising tin and a material selected from the group consisting of copper, arsenic, and antimony; and   a stainless steel tube, wherein the sputter material is connected to the stainless steel tube to form a sputter target.   
     
     
         29 . The sputter target of  claim 28 , wherein the sputter material comprises a tin oxide. 
     
     
         30 . The sputter target of  claim 28 , wherein the sputter material has a copper to tin ratio of about 10 −6  to about 5×10 −2 . 
     
     
         31 . The sputter target of  claim 28 , wherein the sputter target comprises a ceramic tin oxide and copper. 
     
     
         32 . The sputter target of  claim 28 , further comprising a bonding layer bonding the sputter material and the backing tube. 
     
     
         33 . A method of manufacturing a sputter target comprising:
 forming a sputter material comprising tin and a material selected from the group consisting of copper, arsenic, and antimony; and   attaching the sputter material to a backing tube to form a sputter target.   
     
     
         34 . The method of  claim 33 , wherein the step of attaching the sputter material to a backing tube to form a sputter target comprises a thermal spray forming process. 
     
     
         35 . The method of  claim 33 , wherein the step of attaching the sputter material to a backing tube to form a sputter target comprises a plasma spray forming process. 
     
     
         36 . The method of  claim 33 , wherein the step of attaching the sputter material to a backing tube to form a sputter target comprises a powder metallurgy process. 
     
     
         37 . The method of  claim 33 , wherein the powder metallurgy process comprises a hot press process. 
     
     
         38 . The method of  claim 33 , wherein the powder metallurgy process comprises an isostatic process. 
     
     
         39 . The method of  claim 33 , wherein the step of attaching the sputter material to a backing tube to form a sputter target comprises a flow forming process. 
     
     
         40 . The method of  claim 33 , wherein the step of attaching the sputter material to the backing tube comprises bonding the sputtering material to the backing tube with a bonding layer. 
     
     
         41 . A photovoltaic module comprising:
 a plurality of photovoltaic cells adjacent to a substrate; and   a back cover adjacent to the plurality of photovoltaic cells, each one of the plurality of photovoltaic cells comprising:   a barrier layer adjacent to the substrate;   a transparent conductive oxide layer adjacent to the barrier layer;   a buffer layer comprising a dopant adjacent to the transparent conductive oxide layer;   a semiconductor window layer adjacent to the buffer layer;   a semiconductor absorber layer adjacent to the semiconductor window layer, wherein the semiconductor absorber layer comprises a portion of the dopant, diffused from the buffer layer; and   a back contact adjacent to the semiconductor absorber layer.   
     
     
         42 . The photovoltaic module of  claim 41 , further comprising a plurality of positive and negative electrical lines configured to electrically connect the photovoltaic cells to a positive lead and a negative lead. 
     
     
         43 . The photovoltaic module of  claim 42 , further comprising a positive bus bar and negative bus bar configured to electrically connect the photovoltaic cells to a positive lead and a negative lead. 
     
     
         44 . The photovoltaic module of  claim 43 , wherein the positive lead and negative lead are configured to electrically connect the photovoltaic module to at least on additional photovoltaic module to form a photovoltaic array. 
     
     
         45 . A method for generating electricity, the method comprising:
 illuminating a photovoltaic cell with a beam of light to generate a photocurrent; and   collecting the generated photocurrent, wherein the photovoltaic cell comprises:   a barrier layer adjacent to a substrate;   a transparent conductive oxide layer adjacent to the barrier layer;   a buffer layer comprising a dopant adjacent to the transparent conductive oxide layer;   a semiconductor window layer adjacent to the buffer layer;   a semiconductor absorber layer adjacent to the semiconductor window layer, wherein the semiconductor absorber layer comprises a portion of the dopant, diffused from the buffer layer; and   a back contact adjacent to the semiconductor absorber layer.