Study On The Growth And Structure And Optical Properties Of ZnS Thin Films Prepared By Sulfidation

Zn S thin films and Zn S:Cu thin films were prepared by magnetron sputtering method and sulfidation method.XRD,SEM,EDS,AFM,Raman spectroscopy,slow positron beam Doppler broadening energy spectrum and UV-Vis spectrophotometer were used to characterize the structure,morphology,composition,micro-defects and optical properties of the samples.The effects of film thickness,substrate type and curing time on the structure,micro-defects,and optical properties of Zn S and Zn S:Cu films were systematically studied.The test results of Zn S:Cu films of different thicknesses prepared by vulcanizing Zn:Cu metal films of different thicknesses at 500? for 4 h show that the Zn S: Cu films have a cubic structure.The shift of the X-ray diffraction peak and Raman shift indicates that Cu2+ was successfully doped into the lattice of Zn S.With the increase of film thickness,the crystallinity,denseness and stoichiometry of Zn S:Cu thin films all changed significantly.These Zn S: Cu films exhibit low transmittance in the visible light range and have a band gap energy of 3.52-3.62 e V.The slow positron beam Doppler broadening measurement reveals the micro-defects and their types of Zn S: Cu films.The test results of Zn S:Cu films prepared by vulcanizing Zn:Cu metal films deposited on different substrates at 500? for 4 h show that the Zn S:Cu films grown on sapphire substrates have the best crystallinity and the largest grain size.And the concentration of micro-defects is the lowest,while the Zn S:Cu film grown on a single crystal Si substrate has the worst crystallinity,the smallest grain size,the largest concentration of micro-defects,and the type of micro-defects is the most complicated.The study found that the lattice mismatch is not the main factor affecting the growth of the thin film.The growth of the thin film is determined by the surface roughness of the substrate,the adhesion between the substrate and the thin film,and the chemical properties of the substrates.The test results of Zn S thin films prepared by curing at different time at 440?show that the curing time has an important effect on the crystallinity and optical properties of the samples.As the curing time increases,the crystallinity of the samples will improve.However,too long vulcanization time will weaken the crystallinity of the samples.The transmittance of all samples in the visible range is above 60%.The crystallinity of the sample was the best after 6 hours of vulcanization,and the band gap value was as high as 3.49 e V.The samples formed a hexagonal Zn S with low surface free energy.The effects of grain specific surface area and S vapor atmosphere on grain growth were also discussed.The results of the slow positron beam Doppler widening test intuitively revealed the changes in microscopic defects in the Zn S film,which were consistent with the results of XRD and SEM analysis.