Photovoltaic devices and method of making

Abstract

In one aspect of the present invention, a photovoltaic device is provided. The photovoltaic device includes a transparent layer; a first porous layer disposed on the transparent layer, wherein the first porous layer comprises a plurality of pores extending through a thickness of the first porous layer; a first semiconductor material disposed in the plurality of pores to form a patterned first semiconductor layer; and a second semiconductor layer disposed on the first porous layer and the patterned first semiconductor layer, wherein the patterned first semiconductor layer is substantially transparent. Method of making a photovoltaic device is also provided.

1 .- 24 . (canceled) 
     
     
         25 . A photovoltaic device, comprising:
 a transparent layer;   a first semiconductor layer disposed on the transparent layer;   a second semiconductor layer disposed on the first semiconductor layer;   a porous layer disposed on the second semiconductor layer, wherein the porous layer comprises a plurality of pores extending through a thickness of the porous layer; and   a metal layer disposed on the porous layer.   
     
     
         26 . The photovoltaic device of  claim 25 , wherein a portion of the metal layer extends through the plurality of pores in the porous layer to contact the second semiconductor layer. 
     
     
         27 . The photovoltaic device of  claim 25 , further comprising a p+-type semiconductor layer interposed between the second semiconductor layer and the porous layer,
 wherein a portion of the metal layer extends through the plurality of pores in the porous layer to contact the p+-type semiconductor layer.   
     
     
         28 . The photovoltaic device of  claim 25 , further comprising:
 a p+-type semiconductor material disposed in the plurality of pores to form a patterned p+-type semiconductor layer; and   the metal layer is disposed on the porous layer and the patterned p+-type semiconductor layer.   
     
     
         29 . The photovoltaic device of  claim 28 , wherein the patterned p+-type semiconductor layer is compositionally graded across a thickness of the p+-type semiconductor layer. 
     
     
         30 . The photovoltaic device of  claim 28 , further comprising a metal disposed in the plurality of pores in the porous layer, wherein the metal and the p+-type semiconductor material form a compositionally graded layer. 
     
     
         31 . The photovoltaic device of  claim 25 , wherein the first semiconductor material comprises cadmium sulfide. 
     
     
         32 . The photovoltaic device of  claim 25 , wherein the second semiconductor layer comprises cadmium telluride. 
     
     
         33 . A method, comprising:
 disposing a transparent layer on a support;   disposing a first semiconductor layer on the transparent layer;   disposing a second semiconductor layer on the first semiconductor layer;   disposing a porous layer on the second semiconductor layer, wherein the porous layer comprises a plurality of pores extending through a thickness of the porous layer; and   disposing a metal layer on the porous layer.   
     
     
         34 . The method of  claim 33 , further comprising
 disposing a p+-type semiconductor layer on the second semiconductor layer before disposing the porous layer, wherein a portion of the metal layer extends through the plurality of pores in the porous layer to contact the p+-type semiconductor layer.   
     
     
         35 . The method of  claim 34 , wherein the disposing a p+-type semiconductor layer comprises chemically treating the second semiconductor layer to increase the carrier density on a surface of the second semiconductor layer. 
     
     
         36 . The method of  claim 33 , further comprising
 disposing a p+-type semiconductor material in the plurality of pores in the porous layer to form a patterned p+-type semiconductor layer; and   disposing the metal layer on the porous layer and the patterned p+-type semiconductor layer.   
     
     
         37 . The method of  claim 36 , wherein the disposing a p+-type semiconductor material in the plurality of pores comprises selectively chemically treating the second semiconductor layer through the plurality of pores in the porous layer to increase the carrier density in selected regions of the second semiconductor layer. 
     
     
         38 . The photovoltaic device of  claim 25 , wherein the porous layer includes an insulating material. 
     
     
         39 . The photovoltaic device of  claim 25 , wherein the porous layer includes a material having passivation properties for the second semiconductor material. 
     
     
         40 . The photovoltaic device of  claim 25 , wherein the porous layer includes a material selected from the group consisting of silicon oxide, titanium oxide, silicon nitride and combinations thereof. 
     
     
         41 . The photovoltaic device of  claim 25 , wherein the plurality of pores have an average diameter in a range from about 100 nanometers to about 1000 nanometers. 
     
     
         42 . The photovoltaic device of  claim 25 , wherein the porous layer has a thickness in a range from about 10 nanometers to about 200 nanometers. 
     
     
         43 . The photovoltaic device of  claim 27 , wherein the p+-type semiconductor layer includes a heavily doped p+-type material selected from the group consisting of zinc telluride, magnesium telluride, manganese telluride, beryllium telluride, mercury telluride, arsenic telluride, antimony telluride, copper telluride, and combinations thereof. 
     
     
         44 . The photovoltaic device of  claim 44 , wherein the p+-type material further includes a dopant selected from the group consisting of copper, gold, nitrogen, phosphorus, antimony, arsenic, silver, bismuth, sulfur, sodium, and combinations thereof.