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

• Applicant: Professor Dr. Wolfgang Hansen
• Subject Area: Experimental Condensed Matter Physics ; Synthesis and Properties of Functional Materials
• Term: from 2014 to 2021
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 269271569

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.

• DFG Programme: Research Grants
• Co-Investigator: Dr. Christian Heyn