Of Zns Photoelectric Films And Doping On Its Properties

In this study, atomic force microscope (AFM) and scanning electron microscope (SEM) were used to characterize the surface structure and the cross sectional conditions of ZnS thin films deposited on quartz glass by the vacuum evaporation technique. We investigated the transmittance spectrum and photoluminescence spectra of the films. The morphology analysis and observation revealed that thin films formed with wurtzite structure had a small grain size and homogeneous grain size distribution.ZnS:Na and ZnS:Li were fabricated by doping ZnS thin films deposited on glass with Na and Li, their surface structures, transmittance spectrum and photoluminescence were measured under the same conditions. Experimental and theoretical investigations of difference existing in absorption coefficient and photoluminescence in the visible region were presented, which was very meaningful for the technology of doping ZnS thin film.Annealing sample prepared, which is an important method of post anneal treatment, plays a prominent role in improving the properties of thin films. Properties of the thin films such as surface structure, cross sectional conditions, thickness, absorption coefficient and photoluminescence efficiency were observed after annealing as-prepared sample in argon atmosphere at different temperatures from 300℃to 900℃. The study indicated the thickness of thin films increased with the increase of annealing temperature from 300℃~700℃while it decreased when annealing temperature increases after 700℃. The optical absorption efficiency in the visible region reduced while the absorption edge redshifted as the annealing temperature increases. At the same time, with increasing annealing temperature from 300-700℃, the deep level emission(DEL) in photoluminescence spectrum enhanced while it weakened when the temperature was above 700℃. According to experimental observation and theoretical analysis, we thought these results may be associated with film defect varying with annealing temperature.The optical properties of ZnS:Na and ZnS:Li annealed together at different temperature under the same conditions were also studied experimentally and theoretically. It was revealed that optical properties and microstructure of the two films are strongly influenced by annealing temperature. Theoretical discussions were used to explain distinction between them.