Structure Formation Processes and Phase Transitions in Metastable Mixed III/V Semiconductors and Heterostructures

本项目涉及的基本结构的形成过程中的散装和异质界面的亚稳态材料系统的调查。其目的是获得对材料及其异质结构的结构的深刻理解，并利用新的形态相变的驱动力，它们由于其亚稳性而发生相变。结构和形态的定量描述可以关联到新的电子性质。这种理解也将导致新的优化设备应用。为了定量研究四元体系，所使用的纳米分析技术将进一步发展，以适应模拟四元材料的组成，结构和界面形态的需要。应用的实验方法集中在（高分辨率）透射电子显微镜，包括定量图像模拟。实现这一目标所需的其他技术包括高分辨率X射线衍射以及用于研究材料中的应变状态、元素组成和缺陷的核固态物理技术（卢瑟福背散射光谱法、核共振分析、原子化）。

The present project deals with the fundamental structure formation processes in the bulk and at the heterointerfaces of the metastable material systems under investigation. The aim is to gain a profound understanding of the structure of the materials and of their heterostructures and to exploit the driving forces for the novel morphological phase transitions, which they undergo due to their metastability. The quantitative description of the structure and morphology can be correlated to novel electronic properties. This understanding will also lead to novel optimised device applications. In order to quantitatively examine the quaternary systems, the nanoanalytical techniques used will be developed further to suit the needs of simulating composition, structure and interface morphology of quaternary materials. The experimental methods applied focus on (high resolution) transmission electron microscopy including quantitative image simulation. Further techniques, which are necessary to achieve this goal, include high resolution X-ray diffraction as well as techniques of the nuclear solid state physics (Rutherford Backscattering Spectrometry, Nuclear Resonance Analysis, Channeling) for the investigation of the strain state, elemental composition and defects in the materials.