形貌依赖的ZnO阴极射线发光性质研究

采用溶剂热法,通过调节水和乙醇混合液的比例制备了多种形貌的ZnO微米结构。利用扫描电子显微镜（SEM）对ZnO微米结构的形貌及尺寸进行了观察。采用可以实现纳米级微观区域光谱采集的阴极射线发光（CL）技术,对不同形貌的单个粒子的光谱进行精细表征,获得了位置依赖的ZnO阴极射线发光数据。实验结果表明：ZnO材料的发光性质与形貌有关,由于形貌差异导致其局部结晶质量、界面缺陷、表面电荷分布、表面晶面等方面的差异,几种因素共同作用决定其最终的发光性质。     

Eu掺杂GaN薄膜的阴极荧光特性

通过MOCVD方法在蓝宝石衬底上生长GaN薄膜,利用离子注入方法将Eu³⁺离子注入到GaN基质中。X射线衍射结果表明：经过退火处理后,修复了部分离子注入所导致的晶格损伤。利用阴极荧光光谱可得到GaN∶Eu³⁺材料在623 nm处有很强的红光发射,该发射峰来源于Eu³⁺离子的内部4f能级跃迁。另外,Eu³⁺离子注入会在样品中引入电荷转移态,产生408 nm附近的发光。退火处理有助于获得更强的电荷转移态发光和Eu离子特征发光。GaN基质的黄光峰与Eu离子之间存在能量交换,将能量传递给Eu离子,促进Eu离子发光。     

阴极射线发光分析方法及其在新材料研究中的应用

阴极射线发光分析方法是研究材料的结构和能态的重要手段。近年来,这种分析方法的灵敏度和功能等都获得很大改善,特别是在扫描电镜中,将阴极射线发光、二次电子、背散射电子和Ｘ射线特征谱等结合起来形成的综合测量方法,成为研究材料结构和微区性质的有力工具。文章介绍阴极射线发光分析方法的基本原理及其在ＧａＮ,ＳｉＣ,ＺｎＯ和量子线等新材料研究中的应用实例。     

Investigation of Inhomogeneites in Epitaxial AlxGa1−xN Layers Grown on Sapphire

 Procedures for the preparation of bevels and the determination of their geometrical parameters have been developed. Using these procedures study of compositional and optical spatially resolved inhomogeneities of Al_xGa_1−xN layers grown on (0001) sapphire have been studied by EPMA and cathodolu-minescence. It has been found that the nonuniform distribution in depth of Al in epitaxial layers grown under constant conditions is connected with presence of stresses in the layer.     

Synthesis and crystal and defect structures of polycrystalline Cu2SrSnS4 and Cu1.9SrSnS4 powders

The polycrystalline samples of Cu2 – _δSrSnS4 with a trigonal structure were prepared by solid-phase ampoule synthesis with a long annealing time (1944 h), and their crystal lattice parameters were refined and Raman spectra were obtained. For the first time, the effect of defect structure on the lifetimes of photogenerated current carriers in the polycrystalline powders was examined by combining time-resolved microwave photoconductivity and cathodoluminescence methods. A significant increase in the lifetimes during the conversion of Cu₂SrSnS₄ into Cu_1.9SrSnS₄ was found, which was probably due to changes in the defect structure.     

Synthesis,characterization and cathodoluminescence of high‐purity ZnS microbelts

ZnS microbelts with flat morphology have been synthesized through a physical vapor transportation method inside an induction furnace. The structure, morphology and cathodoluminescence properties of ZnS microbelts have been studied using various characterization methods. The width of the ZnS microbelts can be up to several micrometers and the length can reach to tens of µm. Optical measurements indicate that the ZnS microbelts show a sharp UV emission at 337 nm, a weak band at 377 nm, a strong visible luminescence band at 464 nm, and a shoulder at 665 nm. Finally, possible explanations for the optical emissions of ZnS microbelts are discussed.     

ZnO纳米棒在聚［2-甲氧基-5-（2-乙基-己氧基）-1，4-苯撑乙烯撑］固态阴极射线发光器件中的应用研究

利用ZnO纳米棒阵列场发射电极,以SiO₂做为电子加速层制备了固态阴极射线器件,发光层为聚［2-甲氧基-5-（2-乙基-己氧基）-1,4-苯撑乙烯撑］（MEH-PPV）,在交流驱动下得到了MEH-PPV的固态阴极射线发光,探测到了长波峰和短波峰的发射,并和无电子加速层的器件做了比较,证明混合激发模式下的器件在长波长的发光亮度更大. 关键词： 固态阴极射线 ZnO纳米棒阵列 电子加速 电致发光     

一维纳米SiC-CNTs复合结构的生长机制和阴极射线发光

采用直接固相反应法制备了一维SiC-CNTs纳米复合结构。初始反应原料为纯的硅粉和碳纳米管混合物,没有使用任何触媒,在1 400℃温度下获得了一维纳米产物。采用X射线衍射、扫描电子显微镜、拉曼光谱、阴极射线发光光谱研究了产物的结构和光学性质。获得的一维S iC-CNTs纳米复合结构外径约为60nm,长度超过几个微米。CL谱中存在三个发射带,中心位置分别为2.89,2.39,2.22 eV。