(Zn,Cd)S：Cu,Cl发光材料的热释发光

在ZnS中分别掺杂质量分数为5%、7%、10%、15%、20%的CdS,得到一系列(Zn,Cd)S:Cu,Cl粉末电致发光材料样品。测量样品材料的热释发光曲线,发现五个样品在温度-180～-20℃范围内均有两个明显的热释发光峰。CdS含量的变化对材料中陷阱的种类和陷阱深度没有明显的影响,两个峰值温度在-150℃和-50℃附近。Cd离子的掺入改变了材料较深陷阱中载流子的浓度,随着CdS量的增加,使得在-50℃的热释发光峰的相对强度增大。通过测量样品的发光光谱和发光亮度,发现随着CdS含量的增加,样品材料的发射光谱向长波方向移动,发光亮度呈下降的趋势。

Thermoluminescence of (Zn,Cd)S:Cu,Cl Luminescent Material

The direct bandgap semiconductor compound ZnS and CdS were used as multiple based material. The luminescent characteristic were changed by multibase. (Zn,Cd)S:Cu,Cl electroluminescent material specimens were prepared by adding 5%, 7%, 10%, 15%, 20% CdS in ZnS respectively.There were two obvious thermoluminescence peaks from -180℃ to -20℃ in the thermoluminescence curves of the five specimens. The concentration of CdS did not influence the category and the depth of the traps in the material, the temperature of peaks are -150℃ and -50℃. The concentration of CdS did not change the relative intensity of the thermoluminescence peak at -150℃ obviously, the relative intensity were 55.6,46.7,60.2,65.0 and 66.5 respectively, but changed the relative intensity of the thermoluminescence peak a t-50℃.The relative intensity increased with the concentration of CdS increased. When the Cd²⁺ concentration was 5%, the peak of the curve was 7.1, when the Cd²⁺ concentration was 7%, the peak of the curve was 13.4. When the Cd²⁺ concentration was 10%, the peak of the curve was 32.4. When the Cd²⁺ concentration was 15%, the peak of the curve increased to 82.2 quickly and when the Cd²⁺ concentration was 20%, the peak of the curve forther increased to 97.6. The luminescence spectra of specimens moved from shortwave to longwave and the brightness descended as the concentration of CdS increased as shown by the measuring results of luminescence spectra and brightness. We therefore analyzed the result that excessive Cd²⁺ caused the decline of luminance because the replacement of Zn²⁺ by Cd²⁺ in the crystal lattice introduced the defects, and sequently the defects caused the formation of radiationless center. The energy of trapped electrons by the radiationless recombination center turns into the radiationless transition, the α phase which is disadvantageous to luminescence increases when the Cd²⁺ replaces the Zn²⁺ in the crystal lattice synchronously. The Cd²⁺ replaces the Zn²⁺ in the crystal lattice which results in the descending of the bottom of the conduction band, therefore decreases the forbidden band width of based material, which makes the luminescence spectrum moves from shortwave to longwave continuously.The thermoluminescence curves, luminescence spectrum and brightness changed accordingly as the concentration of CdS changed, which makes us find a way to obtain the (Zn,Cd)S:Cu,Cl powder electroluminescent material with the specific luminescence characteristic.