Masters Defense: Rasmus Dalsgaard Schlosser

Shadow Engineering Semiconductor-Superconductor Hybrid Nanowires for Quantum Devices


Nanowires belong in the realm of quasi one-dimensional materials due to their geometrical restrictions, and semiconductor nanowires are at the heart of current state of the art experiments in the field of quantum transport. When coupled with a superconductor, they form a hybrid structure, inheriting the properties of both constituents. This makes them the material of choice in the search for novel qubit systems, proposed to arise from the realisation and control of exotic quantum states. To this end, exceptionally clean materials that exhibit ballistic transport are required. Epitaxial films, formed under ultra high vacuum have proven to fulfil part of this request. Shadow deposition has recently emerged as a viable method for forming the necessary semiconductor-superconductor patterns without the introduction of a chemical etchant. This work expands on the shadow patterning concept by establishing the parameters necessary for precise control of the deposition, in order to create designer architectures, with extensive possibilities in design- and rapid prototyping of hybrid structures. Indium arsenide nanowires with epitaxial aluminium are produced to demonstrate the concept and are subsequently characterised in transport experiments.