准一维ZnO纳米材料/聚合物复合异质结发光器件的构筑及性能研究

As a significant research area in nano optoelectronic technology, nanosale light-emitting devices have attracted more attention, of which PN junction provides an important way to achieve electroluminescent devices. Among the promissing candidates for fabricating PN junctions, Zinc Oxide (ZnO), with a large surface to volume ratio and good optical properties, is believed to be excellent building blocks for semiconductor light sources. However, so far, because of the inevitable compensation effect in intrinsic ZnO materials, the pursuit of stable and reproducible p-ZnO is still undergoing. In this case, heterojunctions of n-ZnO and p-GaN are employed as an alternative approach by considering the similar crystallographic and electronic properties of ZnO and GaN. Nevertheless, GaN has to grow on sapphire substrates, which increases its cost and limits the application of such devices. Moreover, the necessity of a rigid substrate causes this heterojuctions is not appropriate for flexible electronic devices. Hence, this project is to design and fabricate efficient semiconductor light-emitting devices based on controllably prepared quasi-one-dimensional (1D) ZnO materials and polymer hybrid heterojunctions, with optimal structures and properties, as well as to explore their application in flexible electronic devices and electrically pumped laser diodes. The recombination mechanics at the ZnO/polymer interface will be analyzed by a comparison of the device performance under different interface condition. Then, the relationship beteewn device performance and the factors such as morphology, doping technology and device design route,will be established. The effect of material characteristics and construction process on the light emitting performance will be also analyzed, to seek the optimal fabrication parameters. Under the guidance, by decorating the surface with metal particles and doping polymer with conductive particles, we try to improve the devices efficiency. The project is to realize stable semiconducting nanoscale light sources with high luminous intensity, high electro-optical conversion efficiency and longer service lifetime, to extend the application of ZnO in nanosale light emitting devices.

纳光源是纳米光电子学一个重要的研究领域，PN结又是实现电致发光器件的重要途径。氧化锌(ZnO)具有良好的光电特性，是优异的纳光源构建材料之一，但由于本征ZnO材料的自补偿效应，目前性能稳定的P型ZnO材料尚未获得。作为替代，P型氮化镓(GaN)被广泛使用与ZnO搭建PN结，但GaN需在蓝宝石衬底上生长，不适用于柔性电子器件，同时，其昂贵的生产成本也制约了这类器件的实际应用。因此，本项目旨在实现准一维ZnO纳米材料可控制备、结构与性能调控的基础上，结合准一维ZnO材料和P型聚合物在光电性能方面的优势，构建两者的异质结发光器件，探索其在柔性电子器件和电泵浦激光中的应用，揭示材料形貌、掺杂改性、器件构建工艺等因素对器件发光性能的影响规律，建立界面复合机制的物理模型。通过调控器件构筑材料的光电性能，优化异质结的构建工艺，提高发光效率，以期获得高效稳定的纳米发光器件，扩展ZnO在纳光源领域中的应用。

光电功能材料是人类现代文明的物质基础之一，在信息、能源、环境等高新技术领域具有广泛的应用。光电材料的开发和利用已成为世界各国政府、产业界和学术界高度关注的一个具有重大应用前景的前沿基础研究课题。基于上述研究背景，本项目在通过“微环境”控制策略实现ZnO等无机低维半导体材料可控合成的基础上，结合原位表征技术和第一性原理计算深入探讨材料构效演化关系，在此基础成功构筑了多种光电功能器件，并通过掺杂、表面复合、尺寸效应、异质结构、应力调控等精细控制实现光电功能材料和器件性能提升。在本课题资助下，本研究团队共发表SCI论文14篇（均标注本项目资助，其中影响因子大于10的5篇，应邀撰写综述3篇），获得授权中国专利1项（201510437401.8），参加国际国内学术会议10余人次（其中口头报告10人次），协助培养博士研究生2名、硕士研究生7名（3名在读，预计2018年6月毕业），三人获得研究生国家奖学金。主要成果如下：a)选择合适催化剂进行极性面诱导，气相合成了高质量单晶微纳螺旋结构；b)在ZnO材料的合成中添加Ge元素，获得的日盲紫外响应的高质量单晶Zn2GeO4纳米线；c)采用单一前驱体并在气相合成过程中引入微扰，一步法合成P型单晶GaSe纳米带，克服了之前采用两种前驱物在反应产物中引入杂质的难题；d)换用低熔点源头通过气相合成法制备SnS纳米带和大尺度SnS2纳米片，解决了该材料走向实际应用的瓶颈；e)实时研究了电子束辐照对Zn2GeO4纳米线电输运性能影响；f)揭示了材料光电性能与几何形态的依赖关系；g)揭示了多元CdS1-xSex材料光电响应对化学计量的依赖性；h)通过在ZnO纳米线与钙钛矿复合，将本征光谱响应范围由紫外拓展至近红外区域（760 nm）；i)通过快速简便的液相离子交换法获得异质结构，提出一种优化半导体光电探测器性能的新途径。