Self-adjusted hybrid structures consisting of a semiconductor quantum dot and a plasmonic nanostructure in droplet etched nanoholes

在本项目中，将制作和研究由单个外延半导体量子点和金属纳米结构非常接近（即几纳米接近）的新型混合系统。作为中心方面，该制造方法允许在纳米孔中自调节量子点和金属纳米结构。这使得几何形状和距离具有良好的定义和控制。混合结构将通过分子束外延和局部液滴蚀刻纳米孔到半导体表面来制造。除了我们近年来建立的液滴蚀刻和随后的过度生长过程外，主要方面是半导体量子点中的量子化激子态与金属纳米结构中的局域等离子体激发之间的近场耦合效应。我们预期激子和等离激元模式都会受到影响。由于金属纳米结构具有光学纳米天线的作用，在靠近杂化纳米结构的地方，电磁场会发生强烈的改变。除了紧凑的金属纳米粒子外，我们还将研究孔或环型纳米结构。计划在单杂化结构上进行光谱学研究，其中DC-Stark效应将在实验中用于进一步调谐。最后，通过数值模拟来理解实验结果。

In this project novel hybrid systems consisting of a single epitaxial semiconductor quantum dot and a metallic nanostructure in very close, i.e., a few nanometer proximity will be fabricated and studied. As a central aspect the fabrication method allows for self-adjusting the quantum dot and the metallic nanostructure in a nanohole. This makes well-defined and controlled geometries and distances. The hybrid structures will be fabricated with molecular beam expitaxy and local droplet etching of nanoholes into a semiconductor surface. The main aspects are aside from the droplet-etching and the subsequent overgrowth process, which we have established in the recent years, the near-field coupling effects between the quantized excitonic states in the semiconductor quantum dot and the localized plasmonic excitation in the metallic nanostructure. We expect both an influence on the exciton and the plasmon modes. The electromagnetic field will be strongly modified in close proximity to the hybrid nanostructure, because the metal nanostructure acts as an optical nanoantenna. Aside from compact metallic nanoparticles we will also study hole- or ring-type nanostructures. Optical spectroscopy on single hybrid structures is planned, in which the DC-Stark effect will be employed for further tuning during the experiments. Finally, numerical simulations will be performed in order to understand the experimental results.