| ZnS belongs to Ⅱ-Ⅵ compound semiconductor with a wide direct gap of 3.7eV which is widely used in solar cells and LED.In CIGS solar cells, ZnS can be used as a buffer layer to replace CdS, it is non-toxic, environmentally friendly,and it has wider gap.In this study, ZnS films are prepared by CBD, using zinc sulfate, thiourea as the raw material, ammonia as an agent.It was found systematically that the composition concentration, the deposition temperature and deposition time have the influence on the structure, the surface morphology, the film composition, the transmittance and the band gap of the thin films by employing many analysis methods including XRD, SEM, EDS and UV-vis.1. Changes in the composition solution has a significant impact on the film properties.Improving the reaction mixture of zinc, thiourea, ammonia sulfuric acid concentration, due to the increase of Zn2+、S2-、OH-, the film deposition rate will be improved, the surface morphology of the particles become denser, thin film transmittance decreases.2. Temperature can also promote the reaction mixture Zn2+、S2-、OH- release and hydrolysis, and accelerate the movement of ions inside, so as to promote the film growth, the surface morphology become more compact, the light transmittance film goes lower.3. Since the thickness of the thin film, resulting in the diffraction peak can not be found in the XRD before and after annealing, while increasing the deposition time reaches 10h, diffraction peak can be detected by its Miller index of (111), (220), (311) with cubic ZnS crystal structure.4. After annealing, the S will be lost from film, while annealing in S atmosphere will reduce the loss of S.After Ar/S atmosphere annealing,with the grain growing,the surface becomes more compact, optical properties change better.Annealing in S atmosphere,the films have higher transmittance and wider band gap. |
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