Method and system for manufacturing back contacts of photovoltaic devices

Abstract

A method for manufacturing a photovoltaic device includes a step of depositing one of an amorphous layer of ZnTe and a multilayer stack of Zn and Te adjacent a semiconductor layer. The one of the amorphous layer and the multilayer stack is then subjected to an energy impulse at a temperature equal to or greater than its critical temperature. The energy impulse results in an explosive crystallization to form a polycrystalline layer of ZnTe from the one of the amorphous layer and the multilayer stack.

What is claimed is: 
     
         1 . A photovoltaic device, comprising:
 a semiconductor layer; and   a back contact layer disposed adjacent the semiconductor layer, the back contact layer including a polycrystalline layer formed by explosive crystallization of one of (a) an amorphous layer and (b) a multilayer stack deposited adjacent the semiconductor layer.   
     
     
         2 . The photovoltaic device of  claim 1 , wherein amorphous layer includes amorphous ZnTe, the multilayer stack includes alternating layers of Zn and Te, the semiconductor layer includes CdTe, and the polycrystalline layer formed by the explosive crystallization includes polycrystalline ZnTe. 
     
     
         3 . The photovoltaic device of  claim 1 , wherein the semiconductor layer is disposed adjacent a glass substrate. 
     
     
         4 . The photovoltaic device of  claim 1 , wherein the multilayer stack is deposited onto the semiconductor layer. 
     
     
         5 . The photovoltaic device of  claim 1 , wherein the semiconductor layer includes CdTe and the polycrystalline layer formed by the explosive crystallization includes polycrystalline ZnTe. 
     
     
         6 . The photovoltaic device of  claim 1 , wherein the one of (a) and (b) has a total thickness between about 0.01 microns and about 0.6 microns. 
     
     
         7 . A photovoltaic device, comprising:
 a semiconductor layer; and   a back contact layer disposed adjacent the semiconductor layer, the back contact layer including a polycrystalline layer formed by explosive crystallization of one of (a) an amorphous layer including amorphous ZnTe and (b) a multilayer stack including alternating layers of Zn and Te deposited adjacent the semiconductor layer.   
     
     
         8 . The photovoltaic device of  claim 7 , wherein the semiconductor layer is disposed adjacent a glass substrate. 
     
     
         9 . The photovoltaic device of  claim 7 , wherein the multilayer stack is deposited onto the semiconductor layer. 
     
     
         10 . The photovoltaic device of  claim 7 , wherein the semiconductor layer includes CdTe and the polycrystalline layer formed by the explosive crystallization includes polycrystalline ZnTe. 
     
     
         11 . The photovoltaic device of  claim 10 , wherein the one of (a) and (b) has a total thickness between about 0.01 microns and about 0.6 microns. 
     
     
         12 . A system for manufacturing a photovoltaic device, comprising:
 a chamber for holding a semiconductor layer under a vacuum;   a thin film deposition subsystem configured for depositing one of (a) an amorphous layer and (b) a multilayer stack, adjacent the semiconductor layer; and   an energy impulse generator for subjecting the one of (a) and (b) to an energy impulse at a temperature equal to or greater than its critical temperature for explosive crystallization to cause the explosive crystallization and to form a polycrystalline layer.   
     
     
         13 . The system of  claim 8 , wherein the energy impulse generator is a laser. 
     
     
         14 . The system of  claim 8 , wherein the energy impulse generator is a mechanical stylus.