Sheet manufacturing method, sheet, sheet manufacturing apparatus, and solar cell

Abstract

An inexpensive sheet with excellent evenness and a desired uniform thickness can be obtained by cooling a base having protrusions, dipping the surfaces of the protrusions of the cooled base into a melt material containing at least one of a metal material and a semiconductor material for crystal growth of the material on the surfaces of the protrusions. In addition, by rotating a roller having on its peripheral surface protrusions and a cooling portion for cooling said protrusions, the surfaces of the cooled protrusions can be dipped into a melt material containing at least one of a metal material and a semiconductor material for crystal growth of the material on the surfaces of the protrusions. Thus, a sheet with a desired uniform thickness can be obtained without slicing process.

1 . A sheet manufacturing method, comprising the steps of: 
 cooling a base having protrusions;    dipping surfaces of said protrusions of said cooled base into a melt material containing at least one of a metal material and a semiconductor material; and    forming crystals of said material on the surfaces of said protrusions.    
     
     
         2 . A sheet manufacturing method, comprising the steps of: 
 rotating a roller with protrusions on its peripheral surface and a cooling portion capable of cooling said protrusions;    dipping surfaces of said cooled protrusions into a melt material containing at least one of a metal material and a semiconductor material; and    forming crystals of said material on the surfaces of said protrusions.    
     
     
         3 . The sheet manufacturing method according to  claim 1 , wherein said protrusions have at least one of dot-like protrusions and linear protrusions.  
     
     
         4 . The sheet manufacturing method according to  claim 2 , wherein said protrusions have at least one of dot-like protrusions and linear protrusions.  
     
     
         5 . The sheet manufacturing method according to  claim 1 , wherein said protrusions have at least one of dot-like protrusions and linear protrusions in addition to planar protrusions.  
     
     
         6 . The sheet manufacturing method according to  claim 2 , wherein said protrusions have at least one of dot-like protrusions and linear protrusions in addition to planar protrusions.  
     
     
         7 . The sheet manufacturing method according to  claim 1 , wherein said protrusions are coated with a coating material of at least one of silicon carbide, boron nitride, silicon nitride and pyrolitic carbon.  
     
     
         8 . The sheet manufacturing method according to  claim 2 , wherein said protrusions are coated with a coating material of at least one of silicon carbide, boron nitride, silicon nitride and pyrolitic carbon.  
     
     
         9 . The sheet manufacturing method according to  claim 1 , wherein crystal growth of said material starts from said protrusions.  
     
     
         10 . The sheet manufacturing method according to  claim 2 , wherein crystal growth of said material starts from said protrusions.  
     
     
         11 . A sheet produced by cooling a base having protrusions, dipping surfaces of said protrusions of said cooled base into a melt material containing at least one of a metal material and a semiconductor material, wherein said sheet has a curve portion obtained by forming crystals of said material from protrusions on the surface of said base in a curved shape.  
     
     
         12 . A sheet produced by cooling a base having at least one of dot-like protrusions and linear protrusions in addition to planar protrusions and dipping surfaces of said protrusions of said cooled base into a material containing at least one of a metal material and a semiconductor material, wherein said sheet has curved portions and planar portions obtained respectively by forming crystals of said material from said dot-like protrusions or linear protrusions on the surface of said base in a curved shape and by forming crystals of said material from planar protrusions on the surface of said substrate in a planar shape.  
     
     
         13 . A sheet manufacturing apparatus, comprising: 
 a roller having on its peripheral surface protrusions and a cooling portion for cooling said protrusions; and    a crucible including a melt material containing at least one of a metal material and a semiconductor material and capable of dipping said protrusions into said melt by rotation of said roller.    
     
     
         14 . A solar cell produced by forming an electrode on a sheet formed by cooling a base with protrusions and dipping the surfaces of said protrusions of said cooled base into a melt material containing at least one of a metal material and a semiconductor material, wherein said sheet has curved portions obtained by forming crystals of said material from said protrusions on the surface of said base in a curved shape.  
     
     
         15 . A solar cell produced by forming an electrode on a sheet formed by cooling a base with at least one of dot-like protrusions and linear protrusions in addition to planar protrusions and dipping a surface of said cooled base into a melt material containing at least one of a metal material and a semiconductor material, wherein said sheet has curved portions and planar portions obtained respectively by forming crystals of said material from said dot-like protrusions or linear protrusions on the surface of said base in a curved shape and by forming said crystals of said material from said planar protrusions on the surface of said base in a planar shape.  
     
     
         16 . The silicon sheet manufacturing apparatus of manufacturing a silicon sheet by solidifying a silicon melt by rotation of a cooling roller for crystal growth, characterized in that said cooling roller has in its surface protrusions arranged in a dot-like pattern or in a linear pattern when viewed from above.  
     
     
         17 . The silicon sheet manufacturing apparatus according to  claim 16 , characterized in that a space between said protrusions is in a V or U like shape.  
     
     
         18 . The silicon sheet manufacturing apparatus according to  claim 16 , characterized in that the surface of said cooling roller is covered with an SiC film.  
     
     
         19 . The silicon sheet manufacturing apparatus according to  claim 17 , characterized in that a pitch of said V or U grooves is at least 0.05 mm and at most 5 mm.  
     
     
         20 . The silicon sheet manufacturing apparatus according to  claim 16 , wherein a height of said protrusions is at least 0.05 mm and at most 5 mm.  
     
     
         21 . A silicon sheet manufacturing method of manufacturing a silicon sheet by solidifying a silicon melt by rotation of a cooling roller for crystal growth, characterized in that said crystals grow from protrusions of said cooling roller arranged in a dot-like pattern or in a linear pattern when viewed from above.  
     
     
         22 . A solar cell produced by rotating a roller having on its peripheral surface protrusions having at least one of dot-like protrusions and linear protrusions and a cooling portion for cooling said protrusions, and dipping surfaces of said cooled protrusions into a silicon melt so that silicon crystals grow on the surfaces of said protrusions.