Synthesis of Cu(In_1-xGa_x)Se₂ powder by using a metal source and the solvothermal method

The synthesis of CIGS powder has frequently been studied for use in depositing thick films for solar cell applications. The synthesis of CIGS using a salt source and the solvothermal method has been reported. However, reports on the synthesis using a metal source of relatively low cost are a few. In this study, we selected the solvothermal method and metal sources as raw materials. The effects of the reaction temperature, the mixing of ions, and the Ga source on the phase, the morphology, and the particle size of the powder were observed. For synthesis with a Ga metal source, because the Ga ion, which controls the reaction rate, wasn't mixed uniformly in the solvent, CIS and small amounts of CIGS were synthesized. When the uniformity of Ga ions was increased by using a rapid stirring process, the CuIn_0.6Ga_0.4Se₂ phase was mainly synthesized. In the case of GaCl₃, which has a higher solubility than Ga metal, the CuIn_0.4Ga_0.6Se₂ phase and small amounts of CIS were synthesized. The synthesis of CIGS powder by using a metal source was strongly related to the mixing of Ga ions.