Abstract: We report the deposition and structural characterization of zinc sulfide (ZnS) thin films by chemical bath deposition (CBD) from a bath containing thiourea,ZnSO4,and ammonia in aqueous solution.The XRF and XRD analysis of as-deposited and annealed films show that the films have cubic ZnS structure with Zn(OH)2.Transmission measurements show that the optical transmittance is about 90% when the wavelength is over 500nm.The band gap (Eg) value of the deposited film is about 3.51eV.The effect of the ZnS buffer layer deposition time on device performance is studied.The result shows that the cell performance with a CBD-ZnS buffer layer deposited for 25~35min is best.The performance of CIGS solar cells with different buffer layers is compared.These results suggest that CBD-ZnS thin film can alternate CBD-CdS thin film as the buffer layer of CIGS solar cells.

Key words: chemical bath deposition, ZnS thin films, Cu(In,Ga)Se2 solar cells