Characterization of the ZnS thin film buffer layer for Cu(In, Ga)Se2 solar cells deposited by chemical bath deposition process with different solution concentrations

► We gained ZnS film with 3.8 eV Eg. ► The optimal concentration of SC(NH2)2 and NH4OH for CBD-ZnS is 0.3 and 1.5 M respectively. ► The heterogeneous and homogeneous process happens considerably related to the concentrations of SC(NH2)2 and NH4OH.