Solar Cell With Selectively Doped Conductive Oxide Layer And Method Of Making The Same

Abstract

A method of making a coated substrate having a transparent conductive oxide layer with a dopant selectively distributed in the layer includes selectively supplying an oxide precursor material and a dopant precursor material to each coating cell of a multi-cell chemical vapor deposition coater, wherein the amount of dopant material supplied is selected to vary the dopant content versus coating depth in the resultant coating.

The invention claimed is: 
     
         1 . A method of making a coated substrate having a coating layer with a dopant selectively distributed in the coating layer, comprising the steps of:
 supplying a coating precursor material to coating cells of a multi-cell chemical vapor deposition coater;   supplying a dopant precursor material to coating cells of a multi-cell chemical vapor deposition coater;   controlling the supply of at least one of the coating precursor material and the dopant precursor material to define a coating composition having a selected ratio of the dopant precursor material to the coating precursor material at the coating cells; and   depositing the coating composition onto a substrate to form a doped coating layer,   wherein the ratio of the dopant precursor material to the coating precursor material is selected to define a desired dopant content versus coating depth profile of a resultant doped coating.   
     
     
         2 . The method of  claim 1 , wherein at least a portion of the coating cells are individually connected to a coating precursor supply and a dopant precursor supply. 
     
     
         3 . The method of  claim 1 , wherein the coating layer is a transparent conductive oxide layer. 
     
     
         4 . The method of  claim 1 , wherein the coating precursor material comprises a precursor material for an oxide coating comprising one or more of Zn, Fe, Mn, Al, Ce, Sn, Sb, Hf, Zr, Ni, Zn, Bi, Ti, Co, Cr, Si, In, or an alloy of two or more of these materials. 
     
     
         5 . The method of  claim 1 , wherein the dopant precursor material comprises at least one dopant selected from F, In, Al, P, and Sb. 
     
     
         6 . The method of  claim 1 , including controlling the supply of at least one of the coating precursor material and the dopant precursor material such that the dopant is non-uniformly distributed within the tin oxide layer. 
     
     
         7 . The method of  claim 1 , wherein the coating precursor material comprises a tin oxide precursor to form a tin oxide layer and the dopant precursor material comprises a fluorine precursor. 
     
     
         8 . The method of  claim 7 , wherein a fluorine content is higher at a top of the tin oxide layer than near a bottom of the tin oxide layer. 
     
     
         9 . The method of  claim 7 , wherein a fluorine content is lower at a top of the tin oxide layer than near a bottom of the tin oxide layer. 
     
     
         10 . The method of  claim 7 , wherein a fluorine content is higher in a middle region of the tin oxide layer than at a top or bottom of the tin oxide layer. 
     
     
         11 . A solar cell, comprising:
 a first substrate having a first surface and a second surface;   a first conductive layer over at least a portion of the second surface, wherein the first conductive layer is a transparent conductive oxide layer incorporating a dopant material, wherein the dopant material is selectively distributed in the conductive layer;   a semiconductor layer over the transparent first conductive layer; and   a second conductive layer over at least a portion of the semiconductor layer.   
     
     
         12 . The solar cell of  claim 11 , further comprising an undercoating layer between the second surface and the first conductive layer. 
     
     
         13 . The solar cell of  claim 11 , further comprising a second substrate over the second conductive layer. 
     
     
         14 . The solar cell of  claim 11 , wherein the first conductive layer comprises oxides of one or more of Zn, Fe, Mn, Al, Ce, Sn, Sb, Hf, Zr, Ni, Zn, Bi, Ti, Co, Cr, Si, In, or an alloy of two or more of these materials. 
     
     
         15 . The solar cell of  claim 14 , wherein the first conductive layer comprises at least one dopant selected from F, In, Al, P, and Sb. 
     
     
         16 . The solar cell of  claim 15 , wherein the first conductive layer comprises fluorine-doped tin oxide layer. 
     
     
         17 . The solar cell of  claim 16 , wherein the fluorine is non-uniformly distributed within the tin oxide layer. 
     
     
         18 . The solar cell of  claim 17 , wherein a fluorine content is higher at a top of the tin oxide layer than near a bottom of the tin oxide layer. 
     
     
         19 . The solar cell of  claim 1 , wherein the semiconductor layer is selected from monocrystalline silicon, polycrystalline silicon, amorphous silicon, cadmium telluride, and copper indium celenide/sulfide. 
     
     
         20 . A chemical vapor deposition system, comprising:
 at least one coater having a plurality of coating cells, wherein the coating cells are individually connected to respective coating supply sources comprising at least one oxide precursor material and at least one dopant material.