Quaternary co-electrodeposition of the Cu2ZnSnS4 films as potential solar cell absorbers

Cu2ZnSnS4 (CZTS) films are successfully prepared on Mo substrate by electrochemical epitaxial method. An electrolyte contains 0.124 M CuSO4·5H2O, 0.14 M ZnSO4, 0.13 M SnCl2·2H2O, 0.16 M Na2S2O3·5H2O, 2.25 M NaOH, 1.36 M C6H5Na3O7, 1.00 M C4H6O6. The equilibrium potential for quaternary co-electrodeposited solution is set at −1.1 ∼ −1.20 V. The results show that elements are deposited in the following sequence: Cu/S/Zn/S/Cu/S/Sn/S…. The ternary and quaternary compounds are formed with the increasing temperature during annealing. Finally the CZTS film can be well formed at 550 °C. The resistivity of CZTS is about 5.6 × 104 Ω cm.