【作者】 张保花；

【导师】 简基康； 郑毓峰；

【作者基本信息】 新疆大学 ， 凝聚态物理， 2008， 硕士

【摘要】 半导体纳米材料由于具有优异的的光、电、热、磁等物性,有非常广阔的应用前景,因而受到广泛的关注。CdS是一种非常重要的Ⅱ-Ⅵ族半导体材料,具有较大的禁带宽度(2.42ev),在光电子器件领域有重要的应用前景。CdS纳米材料在当前纳米材料研究中占有重要的位置,制备出形貌尺寸可控的纳米材料是制备合成工艺研究的重要目标之一。在制备CdS纳米材料的各种工艺中,水热-溶剂热法是一种重要的方法,受到研究者广泛的关注。本文采用低温水热法制备出了由CdS纳米颗粒自组装的CdS亚微米-微米球,讨论了低温水热制备纳米粉体的参数(反应时间、不同溶剂等)对产物的影响;采用溶剂热法(乙二胺溶剂)制备出了CdS纳米棒,系统讨论了制备过程中各种参数(反应时间、反应温度、不同镉源、溶剂热再结晶等等)对其一维生长行为的影响,分析了可能的生长机制。通过X射线衍射(XRD)、扫描电子显微镜(SEM)、高倍透射电子显微镜(HRTEM)等测试手段对产物的物相和形貌、微结构进行了讨论;通过光致发光谱(PL)和拉曼谱(Raman)对产物的光学性质进行了分析讨论,得出如下主要结论:1、不同反应体系合成不同形貌的CdS纳米晶:水热法合成了CdS球状微晶,在乙二胺溶剂中合成得到CdS纳米棒;反应温度、反应时间是水热-溶剂热合成CdS纳米晶的关键因素。2、在乙二胺溶剂中,选用不同的镉源影响CdS纳米棒的一维生长行为;采用添加剂辅助溶剂热再结晶的工艺,能够使六方相CdS纳米颗粒转变为CdS纳米棒;在此过程中,不同的添加剂,对CdS纳米棒重结晶生长有不同的影响:硫脲和Na2S2O3能够促进CdS纳米棒的生长,而S粉无此效果;结果分析表明CdS纳米棒是由纳米颗粒取向结晶生长而成。3、产物的光谱图分析显示:CdS纳米晶的拉曼(Raman)谱峰出现红移,而CdS纳米晶的光致发光(PL)谱峰出现蓝移。更多还原

【Abstract】 Nano-scaled semiconducting materials have attracted considerable attentions due to their unique potential applications in future nanodevices. AmongⅡ-Ⅵgroup, CdS is an important semiconductor with direct band gap of about 2.42ev, and has wide applications in optoelectronic devices. It is still a challenging task to achieve morphology- and size- controlled growth of CdS nanostructures by a facile technique. Number work has shown technological perspective of hydro- and solvothermal routes to CdS nanostructures because of their facility, low cost and large scale production.The dissertation mainly focused on syntheses of CdS nanocrystals by the two techniques.CdS submicro- and micro-spheres assembled by nanoparticles were synthesized by hydrothermal route at low temperature. One-dimensional nanostructures, nanorods of CdS, were synthesized by solvothermal technique using ethylenediamine as solvent. The influences of synthetic conditions on the growth of CdS nanostructures were studied in details and their growth mechanisms were discussed.X-ray diffraction (XRD), Scanning electron microscopy (SEM), transmission electron microscopy (TEM)and high resolution TEM (HRTEM) were employed to examine the structures, morphologies and micro-structure of the products. The optical properties of products were analyzed by Photoluminescence (PL) spectra and Raman spectra (Raman). The main results of the dissertation are summarized as follows:1、Solvents, reaction temperature and reaction time were key factors of hydro- and solvothermal synthesing CdS nanocrystals.2、The different cadmium sources would affect the structures and morphologies of the products grown in ethylenediamine. The evolution of CdS nanorods from nanoparticles was achieved by solvothermal re-crystallization technique assisted by proper additives. It was found that thiourea and Na2S2O3 could facilitate one-dimensional growth of CdS nanorods.3、The Raman modes of CdS nanocrystals appear a red shift , which is believed to be related with size-effect and crystallinity of the products, and the Photoluminescence spectra of CdS nanocrystals appear a blue shift.更多还原