Alban Morelle

Holes in germanium nanowires have recently attracted interest as a promising platform for the implementation of spin qubits. In addition to low hyperfine interaction, a strong and tunable spin-orbit coupling arises from the heavy-hole light hole mixing in these systems.
Owing to these properties, ultrafast and fully electric qubits have recently been demonstrated in VLS Si/Ge core/shell nanowires and Ge hut wires.
In our project, we propose an alternative, potentially scalable approach based on selectively area growth of in-plane Ge nanowires. Low-temperature magneto-transport measurements are performed to characterize material quality and transport properties. We observe diffusive coherent transport phenomena such as universal conductance fluctuations and weak-antilocalization, the latter indicating strong spin-orbit interaction. Extracting characteristic scales as mean free path, phase coherence length and spin-orbit interaction length, we assess successive improvements on the fabrication process and identify critical directions to move towards further devices as e.g. quantum dots