Masked droplet etching for site-controlled quantum structures

• Applicant: Dr. Christian Heyn
• Subject Area: Experimental Condensed Matter Physics
• Term: since 2019
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 414041112

Quantum effects have been recognized to be very promising for future information and communication technologies. In this field, semiconductor quantum dots (QDs) represent essential building blocks which can act, e.g., as Qubits for quantum computing or as sources for single entangled photons for quantum communication. Often epitaxial QDs are used that are created in a self-assembled fashion using Stranski-Krastanov growth or droplet epitaxy. However, these dots are located randomly, i.e., without significant lateral order. To overcome this issue, the present project focusses on a novel approach for the molecular beam epitaxy (MBE)-based fabrication of site-controlled semiconductor quantum structures. In detail, metal droplets are deposited on a semiconductor surface through pinholes in a mask for site control. The droplets etch nanoholes into the surface, which are finally filled with a material different from the substrate for functionalization. We plan to study in this project the development of MBE compatible masking techniques, the influence of process parameters and materials, and the realization of versatile nanostructures by hole filling like quantum dots, quantum rings, self-aligned quantum dot molecules, and ultra-short nanopillars.

• DFG Programme: Research Grants
• Co-Investigator: Professor Dr. Wolfgang Hansen