ZnS薄膜制备和光学性能研究

采用化学水浴法,以硫酸锌、硫脲、联氨、氨水和去离子水为反应前驱物制备ZnS薄膜。采用SEM、EDS、XRD和透射光谱分析方法,研究反应前驱物中氨水以及联氨的浓度对ZnS薄膜形貌、成分、结构和光学性能的影响,同时对ZnS薄膜的形成机理做进一步分析。结果表明:ZnS薄膜由纳米颗粒组成,这些ZnS纳米颗粒为非晶态结构。ZnS薄膜中S与Zn原子比最大为0.79∶1,薄膜中夹杂少量ZnO或Zn(OH)2。ZnS薄膜在可见光波段的透过率大于80%,禁带宽度为3.74～3.84 eV。氨水和联氨浓度对薄膜形貌、成分和光学性能有较大的影响。当反应前驱物中氨水浓度为0.5～0.8 mol/L、联氨浓度为0.5～1.0 mol/L时,溶液中的化学反应以在衬底上发生的离子-离子反应占主导作用,能在衬底上形成致密且颗粒大小分布均匀的ZnS薄膜,S与Zn的原子比接近1∶1。

Research of the Preparation and Optical Characterization of ZnS Thin Films

ZnS thin films were prepared by the chemical bath deposition(CBD) using zinc sulfate,thiourea,hydrazine,ammonia and de-ionized water as the precursors.The morphology,stoichiometric proportion,structure and optical properties of the ZnS thin films prepared at different ammonia and hydrazine concentrations were investigated by scanning electron microscopy(SEM),energy dispersive spectrometer(EDS),X-ray diffraction(XRD) and UV-VIS spectrophotometer.Furthermore,the formation mechanism of the ZnS film was analysed.The results reveal that the morphology of the ZnS films is constitutive of nano-particles,and these nano-particles are amorphous structure.The highest atom ratio of S and Zn in the ZnS thin films reaches 0.79∶1,which means that the films contain a small amount of ZnO or Zn(OH)2.The optical transmission of the ZnS films is over 80% in the visible region with wider band gap energy between 3.74 and 3.84 eV.The morphology,stoichiometric proportion and optical properties of the ZnS thin films were affected by the concentrations of ammonia and hydrazine greatly.The ion-by-ion mechanism plays a dominant role of the chemical reactions at the substrate in the reaction precursor solution,which leads to the formation of the ZnS films at the substrate with compact and uniform particles,and the atom ratio of S and Zn is close to 1∶1 at the concentration of 0.5-0.8 mol/L of ammonia and 0.5-1.0 mol/L hydrazine in precursors.