Low-hydrogen photovoltaic cell

Abstract

A low-hydrogen photovoltaic cell is disclosed. The photovoltaic cell may contain less than 5% hydrogen. In one aspect, the photovoltaic cell may contain substantially no hydrogen, that is, the photovoltaic cell may be substantially hydrogen free. The photovoltaic cell includes a substrate and an absorber deposited on to the substrate. The absorber may typically include elements from group 11, group 12, and group 13 of the Periodic Table, for example, copper, indium, and gallium. The absorber may be treated with selenium and/or sulfur to produce a CIGS or CIGSS-type photovoltaic cell. The low-hydrogen photovoltaic cell may fabricated by a method and apparatus adapted to control metalloid vapor delivery, for example, in a low-hydrogen or hydrogen free atmosphere.

1 - 63 . (canceled)  
   
   
       64 . A photovoltaic cell comprising: 
 a substrate; and    an absorber deposited on to the substrate, the absorber comprising elements from each of group 11, group 12, and group 13 of the Periodic Table, and less than  5 % hydrogen.    
   
   
       65 . The photovoltaic cell as recited in  claim 64 , wherein the absorber comprises less than 1% hydrogen.  
   
   
       66 . The photovoltaic cell as recited in  claim 65 , wherein the absorber comprises substantially no hydrogen.  
   
   
       67 . The photovoltaic cell as recited in  claim 64 , wherein the absorber further comprises at least one of selenium and sulfur.  
   
   
       68 . The photovoltaic cell as recited in  claim 64 , wherein the substrate comprises a metallic substrate.  
   
   
       69 . The photovoltaic cell as recited in  claim 64 , wherein the substrate comprises at least one of steel, stainless steel, titanium, and glass.  
   
   
       70 . The photovoltaic cell as recited in  claim 64 , wherein the cell further comprises an electrical conductor mounted to the absorber.  
   
   
       71 - 74 . (canceled)  
   
   
       75 . The photovoltaic cell as recited in  claim 64 , wherein the absorber comprises copper, indium, and gallium.  
   
   
       76 . The photovoltaic cell as recited in  claim 64 , wherein the substrate comprises a metallic foil.  
   
   
       77 . The photovoltaic cell as recited in  claim 76 , wherein the metallic foil has a thickness between about  5  microns and about 1 mm.  
   
   
       78 . The photovoltaic cell as recited in  claim 64 , wherein the photovoltaic cell is more reliable than a photovoltaic cell containing more than about 5% hydrogen.  
   
   
       79 . A method of fabricating a low-hydrogen containing photovoltaic cell from the substrate and absorber recited in claim  1 , the method comprising: 
 introducing the substrate and the absorber to an enclosure;    introducing an element-containing material having little or no hydrogen content to the enclosure;    heating the substrate and the absorber to a first temperature;    independent of the heating of the substrate and the absorber, heating the element-containing material to a temperature sufficient to volatilize the element and release an element-containing vapor into the enclosure;    treating the absorber with at least some of the element-containing vapor; and    cooling the substrate and the absorber to provide a low-hydrogen containing photovoltaic cell.    
   
   
       80 . The method as recited in  claim 79 , wherein the method further comprises introducing a substantially hydrogen-free treatment gas to the enclosure to provide a substantially hydrogen-free reaction atmosphere.  
   
   
       81 . The method as recited in  claim 80 , wherein the substantially hydrogen-free gas comprises at least one of oxygen, argon, helium, selenium vapor and sulfur vapor.  
   
   
       82 . The method as recited in  claim 79 , wherein the method further comprises vacuum purging the enclosure.  
   
   
       83 . The method as recited in  claim 79 , wherein the method further comprises, after reacting, regulating the temperature of the element-containing material at a temperature sufficient to condense at least some of the element from the element-containing vapor on the element-containing material.  
   
   
       84 . The method as recited in  claim 79 , wherein the element-containing material comprises one of sulfur, selenium, tellurium, indium, gallium, sodium, and combinations thereof.  
   
   
       85 . The method as recited in  claim 79 , wherein treating the absorber with at least some of the element-containing vapor comprises one of reacting the element-containing vapor with the absorber and providing an overpressure of the element-containing vapor to the absorber.  
   
   
       86 . The method as recited in  claim 79 , wherein cooling the element-containing material comprises cooling the element-containing material wherein substantially all of the unreacted element-containing vapor condenses on the element-containing material.  
   
   
       87 . The method as recited in  claim 79 , wherein the method further comprises mounting an electrical conductor to the absorber.