Characterization, cathodoluminescence and field-emission properties of morphology-tunable CdS micro/nanostructures
Characterization, cathodoluminescence and field-emission properties of morphology-tunable CdS micro/nanostructures
复制标题
DOI：
10.1002/adfm.200900295
复制
发表时间：
2009-08
期刊：
影响因子：
--
通讯作者：
T. Zhai;X. Fang;Xijin Xu;Y. Bando;D. Golberg
中科院分区：
文献类型：
--
作者：
T. Zhai;X. Fang;Xijin Xu;Y. Bando;D. Golberg
通过一种简单有效的热蒸发工艺制备了高质量、均匀的具有不同形貌的CdS一维（1D）微/纳米结构，如微米棒、亚微米线和纳米尖。系统地研究了它们的结构、阴极发光和场发射特性。微米棒和纳米尖表现出尖锐的近带边（NBE）发射和宽的深能级（DL）发射，而亚微米线只显示DL发射。沿着沿着锥形纳米尖端朝向较小直径部分观察到DL/NBE强度比的显著降低。这种行为的理解下考虑的缺陷浓度的纳米尖，分析与高分辨率透射电子显微镜（HRTEM）。场发射（FE）测量表明，纳米尖具有最好的FE特性，具有相对较低的开启场（5.28 V/µm）和迄今为止报道的所有一维CdS纳米结构中最高的场增强因子4819。讨论了场增强因子、开启场和阈值场与结构形貌和发射时真空间隙变化的关系。
High-quality, uniform CdS one-dimensional (1D) micro/nanostructures with different morphologies, e.g. microrods, sub-microwires and nanotips, are fabricated through a facile and effective thermal evaporation process. Their structural, cathodoluminescence and field-emission (FE) properties are systematically investigated. Microrods and nanotips exhibit sharp near band edge (NBE) emission and broad deep level (DL) emission, whereas sub-microwires show only the DL emission. A significant decrease in a DL/NBE intensity ratio is observed along a tapered nanotip towards a smaller diameter part. This behavior is understood under consideration of defect concentrations in the nanotips, as analyzed with high-resolution transmission electron microscopy (HRTEM). Field-emission (FE) measurements show that the nanotips possess best FE characteristics with a relatively low turn-on field of 5.28 V/µm and the highest field-enhancement factor of 4819 among all 1D CdS nanostructures reported to date. The field-enhancement factor, turn-on and threshold fields are discussed related to structure morphology and vacuum gap variations under emission.