Solution processing of kesterite semiconductors

Abstract

Methods for depositing a kesterite film comprising a compound of the formula: Cu 2-x Zn 1+y Sn(S 1-z Se z ) 4+q , wherein 0≦x≦1; 0<y≦1; 0≦z≦1; −1≦q≦1, generally include contacting a hydrazine-based solvent, a source of Cu, a source of Sn, a source of Zn carboxylate, a source of at least one of S and Se, under conditions sufficient to form a solution substantially free of solid particles; applying the solution onto a substrate to form a thin layer; and annealing the thin layer at a temperature, pressure, and length of time sufficient to form the kesterite film. Also disclosed are hydrazine-based precursor solutions for forming a kesterite film and a photovoltaic device including the kesterite film formed by the above method.

What is claimed is: 
     
         1 . A hydrazine-based precursor solution for forming a kesterite film, comprising:
 a mixed solution comprising:
 a solution comprising a source of Cu, a source of Sn, and a source of at least one of S or Se and hydrazine; 
 a slurry containing a source of Zn carboxylate particles and hydrazine, wherein the mixed solution stabilizes the source of the Zn carboxylate to form the hydrazine-based precursor solution. 
   
     
     
         2 . The hydrazine-based precursor solution of  claim 1 , wherein said hydrazine in the mixed solution is in an amount from about  1  weight % to about  99  weight %. 
     
     
         3 . The hydrazine-based precursor solution of  claim 1 , wherein said source of Zn carboxylate particles is at least one of zinc formate and zinc acetate. 
     
     
         4 . The hydrazine-based precursor solution of  claim 1 , wherein said source of Cu is at least one of Cu, CuS, Cu 2 S, Cu formate, and Cu acetate. 
     
     
         5 . The hydrazine-based precursor solution of  claim 1 , wherein said source of Sn is at least one of Sn, SnS, SnS 2 , SnSe, SnSe 2 , Sn formate and Sn acetate. 
     
     
         6 . The hydrazine-based precursor solution of  claim 1 , wherein said source of S or Se is at least one of S and Se.