Phase analysis of Cu(In1 − xGax)Se2 prepared by solvothermal method

For screen printing of Cu(In1 − xGax)Se2 (CIGS) in solar cell application, the synthesis of CIGS powder was examined. The solvothermal method was adopted for CIGS synthesis, as it is known that the method could control particle characteristics easily and produce much amount of powders. The phase change and particle shapes were observed with variation of reaction temperature and time. At low reaction temperature of 210 °C, CuInSe2 (CIS) and CuGaSe2 (CGS) were formed first without CIGS. As reaction temperature increased, CIGS phases of different compositions appeared at 230 °C, but made into one stoichiometric composition at 250 °C. With increase of reaction time at 250 °C, the phase ratio did not change significantly and three phases coexisted.