Devices and methods featuring the addition of refractory metals to contact interface layers

Abstract

Disclosed embodiments include CdS/CdTe PV devices ( 100 ) having a back contact ( 110,112 ) with oxygen gettering capacity. Also disclosed are back contact structures ( 110, 112 ) and methods of forming a back contact in a CdS/CdTe PV device ( 100 ). The described contacts and methods feature a contact having a contact interface layer ( 100 ) comprising a contact interface material, a p-type dopant and a gettering metal.

What is claimed is: 
     
         1 . A method of forming a back contact in a CdS/CdTe PV device comprising:
 providing a sputtering target comprising a contact interface material, a p-type dopant and a gettering metal;   depositing a contact interface layer from the sputtering target to a CdTe device layer; and   depositing an outer metallization layer to the contact interface layer.   
     
     
         2 . The method of  claim 1  further comprising providing the gettering metal in the target as a non-oxide compound of the gettering metal that exhibits a smaller negative enthalpy than an oxide of the gettering metal. 
     
     
         3 . The method of  claim 2  wherein the gettering metal is one of Ti, Zr and Hf. 
     
     
         4 . The method of  claim 2  further comprising providing the gettering metal in the sputtering target as TiTe 2 . 
     
     
         5 . The method of  claim 1  further comprising providing the contact interface material in the sputtering target as ZnTe. 
     
     
         6 . The method of  claim 1  further comprising:
 providing a sputtering target powder; 
 pressing the sputtering target powder into a sputtering target in an inert or reducing atmosphere; and 
 machining the sputtering target in an inert or reducing atmosphere. 
 
     
     
         7 . The method of  claim 1  further comprising depositing the contact interface layer in an inert or reducing atmosphere. 
     
     
         8 . The method of  claim 1  further comprising providing a sputtering target comprising ZnTe, Cu and a gettering metal. 
     
     
         9 . The method of  claim 8  further comprising providing a sputtering target comprising ZnTe, Cu and TiTe 2 . 
     
     
         10 . A CdS/CdTe PV device comprising:
 a superstrate;   one or more TCO layers in physical contact with the superstrate;   an n-type CdS layer in electrical contact with at least one TCO layer;   a CdTe layer in electrical contact with the CdS layer;   a contact interface layer comprising a contact interface material, a dopant and a gettering metal in electrical contact with the CdTe layer; and   an outer metallization layer in electrical contact with the contact interface layer.   
     
     
         11 . The CdS/CdTe PV device of  claim 10  wherein the gettering metal is one of Ti, Zr and Hf. 
     
     
         12 . The CdS/CdTe PV device of  claim 10  wherein the dopant is Cu. 
     
     
         13 . The CdS/CdTe PV device of  claim 10  wherein the contact interface material is ZnTe 
     
     
         14 . The CdS/CdTe PV device of  claim 10  wherein the contact interface layer comprises a dopant, a gettering metal and supplemental Te. 
     
     
         15 . The CdS/CdTe PV device of  claim 10  wherein the contact interface layer comprises Cu, Ti and supplemental Te. 
     
     
         16 . A back contact for a CdS/CdTe PV device comprising:
 a contact interface layer comprising a contact interface material, a dopant and a gettering metal; and   an outer metallization layer in electrical contact with the contact interface layer.   
     
     
         17 . The back contact of  claim 16  wherein the gettering metal is one of Ti, Zr and Hf 
     
     
         18 . The back contact of  claim 16  wherein the dopant is Cu. 
     
     
         19 . The back contact of  claim 16  wherein the contact interface material is ZnTe. 
     
     
         20 . The back contact of  claim 16  wherein the contact interface layer comprises a dopant, a gettering metal and supplemental Te. 
     
     
         21 . The back contact of  claim 16  wherein the contact interface layer comprises Cu, Ti and supplemental Te.