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

在这个项目中，我们将制作和研究由单个外延半导体量子点和非常接近的金属纳米结构组成的新型混合系统，即几个纳米的接近。作为中心方面，该制备方法允许在纳米孔中自调节量子点和金属纳米结构。这使得几何图形和距离得到了很好的定义和控制。这种混合结构将通过分子束外延和局部液滴刻蚀纳米孔到半导体表面来制造。除了我们最近几年建立的液滴刻蚀和随后的生长过程之外，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。我们预计激子模和等离子体激子模都会受到影响。由于金属纳米结构起到了光学纳米天线的作用，电磁场将在接近混合纳米结构的地方进行强烈的修饰。除了致密的金属纳米颗粒外，我们还将研究孔型或环型纳米结构。计划在单个杂化结构上进行光学光谱，其中将在实验期间利用DC-Stark效应进行进一步的调谐。最后，为了更好地理解实验结果，将进行数值模拟。

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.