Multi-junction solar cells and methods and apparatuses for forming the same

Abstract

Embodiments of the present invention generally relate to solar cells and methods and apparatuses for forming the same. More particularly, embodiments of the present invention relate to thin film multi-junction solar cells and methods and apparatuses for forming the same.

1 . A tandem junction photovoltaic device, comprising:
 a first photovoltaic junction; and   a second photovoltaic junction having:   a p-doped microcrystalline silicon layer;   an intrinsic type microcrystalline silicon layer adjacent to the p-doped microcrystalline silicon layer; and   a n-doped amorphous silicon layer adjacent to the intrinsic type microcrystalline silicon layer.   
     
     
         2 . The device of  claim 1 , wherein the second photovoltaic junction further comprising:
 a heavily n-doped amorphous silicon layer adjacent to the n-doped amorphous silicon layer.   
     
     
         3 . The device of  claim 2 , further comprising:
 a metal back layer adjacent to the heavily n-doped amorphous silicon layer.   
     
     
         4 . The device of  claim 3 , wherein the metal back layer is selected from a group consisting of Al, Ag, Ti, Cr, Au, Cu, Pt, alloys thereof and combinations thereof. 
     
     
         5 . The device of  claim 1 , wherein the first photovoltaic junction further comprises:
 a p-doped amorphous silicon layer;   an intrinsic type amorphous silicon layer adjacent to the p-doped amorphous silicon layer; and   a n-doped microcrystalline silicon layer adjacent to the intrinsic type amorphous silicon layer.   
     
     
         6 . The device of  claim 5 , further comprising:
 a n-doped amorphous silicon buffer layer disposed between the intrinsic type amorphous silicon layer and the n-doped microcrystalline silicon layer.   
     
     
         7 . The device of  claim 6 , wherein the p-doped microcrystalline silicon layer, the n-doped amorphous silicon layer, the p-doped amorphous silicon layer and the n-doped microcrystalline silicon layer each comprise silicon. 
     
     
         8 . The device of  claim 1 , further comprising:
 a first transparent conductive oxide layer, wherein the first photovoltaic junction is adjacent to the first transparent conductive oxide layer.   
     
     
         9 . The device of  claim 8 , further comprising:
 a transparent substrate in contact with the first transparent conductive oxide layer.   
     
     
         10 . A tandem junction photovoltaic device comprising:
 a first p-i-n junction, having:
 a p-type amorphous silicon layer; 
 an intrinsic amorphous silicon layer; and 
 a n-type microcrystalline silicon layer; 
   a second p-i-n junction adjacent to the first p-i-n junction, wherein the second p-i-n junction having:
 a p-type microcrystalline silicon layer; 
 an intrinsic microcrystalline silicon layer; and 
 a n-type amorphous silicon layer. 
   
     
     
         11 . The device of  claim 10 , wherein the second p-i-n junction further comprises:
 a heavily doped n-type amorphous silicon layer adjacent to the n-type amorphous silicon layer.   
     
     
         12 . The device of  claim 10 , wherein the first p-i-n junction further comprises:
 a n-type amorphous silicon buffer layer disposed between the intrinsic amorphous silicon layer and the n-type microcrystalline silicon layer.   
     
     
         13 . The device of  claim 10 , wherein the p-type amorphous silicon layer, the n-type microcrystalline silicon layer, the p-type microcrystalline silicon layer and the n-type amorphous silicon layer each comprise silicon. 
     
     
         14 . The device of  claim 10 , wherein the first p-i-n junction has a p-type amorphous silicon carbon layer. 
     
     
         15 . The device of  claim 10 , wherein the first p-i-n junction is adjacent to a transparent conductive oxide layer. 
     
     
         16 . The device of  claim 10 , further comprising:
 a metal back layer adjacent to the second p-i-n junction.   
     
     
         17 . The device of  claim 15 , wherein the transparent conductive oxide layer is adjacent to a transparent substrate. 
     
     
         18 . The device of  claim 10 , wherein the p-type amorphous silicon layer in the first p-i-n junction has a thickness between about 60 Å and about 300 Å, the intrinsic amorphous silicon layer has a thickness between about 1500 Å, and about 3000 Å, and the n-type microcrystalline silicon layer has a thickness between about 100 Å and about 400 Å. 
     
     
         19 . The device of  claim 10 , wherein the p-type microcrystalline silicon layer in the second p-i-n junction has a thickness between about 100 Å and about 400 Å, the intrinsic microcrystalline silicon layer has a thickness between about 10000 Å and about 30000 Å, and the n-type amorphous silicon layer has a thickness between about 100 Å and about 500 Å. 
     
     
         20 . The device of  claim 12 , wherein the n-type amorphous silicon buffer layer has a thickness between about 10 Å and about 200 Å. 
     
     
         21 . A photovoltaic device, comprising:
 a p-type microcrystalline silicon layer;   an intrinsic microcrystalline silicon layer adjacent to the p-type microcrystalline silicon layer;   a n-type amorphous silicon layer adjacent to the intrinsic microcrystalline silicon layer; and   a heavily doped n-type amorphous silicon layer adjacent to the n-type amorphous silicon layer.   
     
     
         22 . The device of  claim 21 , wherein the p-type microcrystalline silicon layer is adjacent to a light absorbing layer. 
     
     
         23 . The device of  claim 22 , wherein the light absorbing layer further comprises:
 a p-type amorphous silicon layer;   an intrinsic amorphous silicon layer adjacent to the p-type amorphous silicon layer; and   a n-type microcrystalline silicon layer adjacent to the intrinsic amorphous silicon layer.   
     
     
         24 . The device of  claim 23 , wherein the n-type microcrystalline silicon layer of the light absorbing layer is in contact with the p-type microcrystalline silicon layer. 
     
     
         25 . The device of  claim 23 , wherein the p-type microcrystalline silicon layer, the n-type amorphous silicon layer, the p-type amorphous silicon layer and the n-type microcrystalline silicon layer each comprise silicon. 
     
     
         26 . The device of  claim 23 , further comprises:
 a n-type amorphous silicon buffer layer between the intrinsic amorphous silicon layer and the n-type microcrystalline silicon layer.   
     
     
         27 . The device of  claim 22 , wherein the light absorbing layer is adjacent to a transparent conductive oxide layer. 
     
     
         28 . The device of  claim 21 , further comprising:
 a metal back layer adjacent to the heavily doped n-type amorphous silicon layer.