Spectroscopy of excitions in single nanorods

半导体纳米结构具有各向异性的光学和电学性质，为自下而上设计纳米器件和光学主动/被动混合纳米结构的光学功能化提供了一类重要的材料。本项目的目的是研究和了解单纳米棒中激子基元激发的维度和方向相关性，以此作为使用它们的先决条件，例如，用于应用目的和基础物理的纳米棒基络合物。重点是纤锌矿类型纳米棒中特殊的高度线偏振发射。以温度、激发能、泵浦功率、纳米棒尺寸和形状、硫化锌壳层厚度和形状、纳米棒环境和生长机制为外部参数，在单纳米棒水平上用光谱学方法研究了胶体CdSe纳米棒中激子的对称性和波函数、激子精细结构、辐射寿命、态密度以及与其他基元激发(声子、带电激子、双激子)的相互作用。为了了解具有不同对称性的紧邻能态的高度极化、定向的发射体(纳米棒)在功能纳米系综中的具体作用，我们研究了更复杂结构中的纳米棒，如排列的纳米棒、纳米棒/染料和纳米棒/金属线复合体，并测定了复合体内部的电子耦合、能量转移、光转换和相互激发。

Semiconductor nanostructures with anisotropic optical and electronical properties present an important material class for bottom-up design of nanodevices and optical functionalization of hybrid optically active/passive nanostructures. This project is aimed at the investigation and understanding of dimensionality and directional dependencies of excitonic elementary excitations in single nanorods as a prerequisite for using them, e.g., in nanorod-based complexes for application purposes and fundamental physics. The focus is on the peculiar high degree of linearly polarized emission in wurtzite-type nanorods. The symmetries and wave functions of excitons in colloidal CdSe nanorods, the excitonic fine structures, the radiative lifetime, the density of states as well as interaction with other elementary excitations (phonons, charged excitons, biexcitons) will be studied by spectroscopy on a single nanorod level with temperature, excitation energy, pump power, nanorod size and shape, ZnS shell thickness and shape, nanorod environment and growth regimes as external parameters. To understand the specific action of highly polarized, oriented emitters with close-lying energy states of different symmetry (the nanorods) in functional nanoensembles, we study nanorods in more complex structures, such as ensembles of aligned nanorods, nanorod/dye and nanorod/metal wire complexes and determine electronic coupling, energy transfer, light conversion and mutual excitation inside the complexes.