Nature of Quantum Localization Probed by Exciton Dynamics in II-VI Semiconductor Alloys

摘要：提出研究II-VI型半导体合金中Anderson局域化的性质。在合金中，在迁移率边缘附近的光生电子-空穴对或激子的寿命与其局域化长度直接相关。因此，这些材料中的激子系统是研究量子局域化的一个模型系统。利用时间分辨光致发光光谱技术研究激子局部化的动力学过程。在温度和合金无序度等不同条件下，测量激子局域化长度、迁移率边缘和局域化长度的临界指数。研究临界指数的普适性以及载流子局域化和激子局域化的根本区别。这些研究可以为物理学量子局域化提供新的认识。非技术文摘：固体中的无序可以引起一个显著的效应，即电子电荷的空间局域化，称为安德森局域化。由于球形无序度几乎是真实材料的普遍特征，安德森局域化同样是确定凝聚态物质的电学、光学和其他物理性质的普遍因素。因此，安德森局域化被认为是凝聚态物理中最重要的课题之一。本研究旨在研究某些在光电器件中有重要应用的半导体合金（含元素周期表II族和VI族元素）的Anderson局域化特性。* * *

9408816 Lin Technical abstract: It is proposed to investigate the nature of Anderson localization in II-VI semiconductor alloys. In the alloys the lifetime of a photogenerated electron-hole pair, or exciton, near the mobility edge is directly correlated to its localization length. Thus the exciton system in these materials represents a model system for studying quantum localization. The dynamics of exciton localization will be probed by time resolved photoluminescence spectroscopy. The exciton localization length, mobility edge, and the critical exponent of the localization length will be measured under different conditions including temperature and the degree of alloy disorder. The universality of the critical exponent and the fundamental differences between charge carrier localization and exciton localization will be investigated. These studies can provide new insight into the physics quantum localization. Non-technical abstract: Disorder in solids can cause a remarkable effect that is the spatial localization of electronic charge, which is called Anderson localization. Since dome degree of disorder is a nearly universal feature of real materials, the Anderson localization is likewise a ubiquitous ingredient in determining electrical, optical, and other physical properties of condensed matter. Therefore, Anderson localization is recognized as one of the most important subjects in condensed matter physics. This proposed research is to study the properties of Anderson localization in certain semiconductor alloys (containing elements from groups II and VI of the periodic table) which have important applications in optoelectronic devices. ***