Growth modes and interfaces of InGaN nanostructures by planar and cross-sectional STM

这个项目的目的是详细了解生长模式和生长机制，这对族-III-氮化物基量子结构的组装和质量非常重要。为了获得详细的结构表征，生长过程中的原位扫描隧道显微镜研究将被用来获得关于该材料系统的生长模式、分凝效应、InGaN量子阱结构中成分起伏的来源、量子点的成核以及它们与生长参数的关系的信息。作为现场实验的补充，将使用掠入射X射线衍射和小角散射、透射电子显微镜、基于同步辐射的X射线衍射和散射以及非原位扫描隧道显微镜进行非原位调查。这种分析工具的组合将使我们能够研究各种结构参数及其分布，如量子点的表面形态、大小和形状，以及量子结构的横向和/或垂直排列的有序性。该项目的样本将由项目I-1中申请的增长资源提供。本项目将进行的实验所获得的结果一方面可以用来理解增长，并与项目III-1密切合作，能够可靠地预测增长参数的影响。另一方面，该项目的结果对于确定适合于项目I-1和I-2所需的优化制造量子点阵列的生长参数将是至关重要的。此外，结构参数的知识对于从理论上描述这种量子结构的电子和光学性质是必不可少的。因此，目前拟议的项目可以为项目III-2和III-3提供有价值的投入参数。将与II-2密切合作处理表面掺杂剂复盖率对生长模式的影响问题。

This project aims at a detailed understanding of the growth modes and growth mechanisms which are important for the assembly and quality of group-III-nitride based quantum structures. For a detailed structural characterization in-situ scanning tunneling microscopy studies during growth will be used to achieve information regarding the growth modes of this material system, segregation effects, the origin of compositional fluctuations in InGaN quantum well structures, and the nucleation of quantum dots as well as their dependence on the growth parameters. The in-situ experiments will be complemented by ex-situ investigations using grazing incidence x-ray diffraction and small angle scattering, transmission electron microscopy, synchrotron radiation based x-ray diffraction and scattering, and ex-situ STM. This combination of analytical tools will allow us to study a wide variety of structural parameters and their distribution, like surface morphology, size and shape of quantum dots, and ordering of the lateral and/or vertical arrangement of quantum structures. Samples for this project will be provided by the growth resources applied for in project I-1. The results obtained from the experiments to be performed in this project may, on the one hand, be used to understand growth and enable reliable predictions on the impact of growth parameters in close cooperation with project III-1. On the other hand, the results of this project will be essential to establish growth parameters suitable for an optimized fabrication of quantum dot arrays as needed for projects I-1 and I-2. In addition, the knowledge of structural parameters is essential for a theoretical description of the electronic and optical properties of such quantum structures. Therefore the presently proposed project can provide valuable input parameters for the projects III-2 and III-3. The issue of the impact of surface dopant coverage on the growth mode will be addressed in close cooperation with II-2.