Method of forming cigs thin film

Abstract

Disclosed herein is a method of forming a CIGS thin film, comprising the steps of: immersing a substrate comprising an electrode into an electrolyte solution comprising Na 2 SO 4 , a water-soluble copper (Cu) precursor, a water-soluble indium (In) precursor, a water-soluble gallium (Ga) precursor, and a water-soluble selenium (Se) precursor; performing electrodeposition in such a way as to apply a direct current (DC) voltage of −0.95V˜−0.85V to the electrolyte solution at room temperature and normal pressure for 10˜120 minutes to form a preliminary CIGS thin film; and heat-treating the preliminary CIGS thin film at 230˜270° C. to form a CIGS thin film.

1 . A method of forming a CIGS thin film, comprising the steps of:
 immersing a substrate comprising an electrode into an electrolyte solution comprising Na 2 SO 4 , a water-soluble copper (Cu) precursor, a water-soluble indium (In) precursor, a gallium (Ga) water-soluble precursor, and a water-soluble selenium (Se) precursor;   performing electrodeposition in such a way as to apply a direct current (DC) voltage of −0.95V˜−0.85V to the electrolyte solution at room temperature and normal pressure for 10˜120 minutes to form a preliminary CIGS thin film; and   heat-treating the preliminary CIGS thin film at 230˜270° C. to form a CIGS thin film.   
     
     
         2 . The method according to  claim 1 , wherein the substrate comprising an electrode is a substrate comprising a molybdenum electrode or a silicon electrode. 
     
     
         3 . The method according to  claim 1 , wherein the electrolyte solution comprises a water-soluble copper (Cu) precursor, a water-soluble indium (In) precursor, a water-soluble gallium (Ga) precursor, and a water-soluble selenium (Se) precursor, each of which is of a concentration of 0.1˜10 mM. 
     
     
         4 . The method according to  claim 1 , wherein the water-soluble copper (Cu) precursor is selected from the group consisting of Cu(NO 3 ) 2 , CuSO 4 , and hydrates thereof. 
     
     
         5 . The method according to  claim 1 , wherein the water-soluble indium (In) precursor is selected from the group consisting of In(NO 3 ) 3 , In 2 (SO 4 ) 3 , and hydrates thereof. 
     
     
         6 . The method according to  claim 1 , wherein the water-soluble gallium (Ga) precursor is selected from the group consisting of Ga(NO 3 ) 3 , Ga 2 (SO 4 ) 3 , and hydrates thereof. 
     
     
         7 . The method according to  claim 1 , wherein the water-soluble selenium (Se) precursor is selected from the group consisting of SeO 2 , H 2 SeO 3 , and hydrates thereof. 
     
     
         8 . The method according to  claim 1 , wherein the electrolyte solution has a pH of 2˜3. 
     
     
         9 . The method according to  claim 1 , wherein an atom ratio of copper, indium, gallium, and selenium in the electrolyte solution is 0.8˜1.2:0.8˜1.2:1.8˜2.2:2.8˜3.2. 
     
     
         10 . The method according to  claim 9 , wherein the atom ratio of copper, indium, gallium, and selenium in the electrolyte solution is 1:1:2:3. 
     
     
         11 . The method according to  claim 1 , wherein the CIGS thin film has an atom ratio of Ga/(In+Ga) of 0.2˜0.4.