Growth and Characterisation of in-plane Ge/Si core/shell nanowires

This work is focused on the development of a platform that can easily accommodate semiconductor spin Qubits. Among all the semiconductor materials, germanium (Ge) appears to be particularly suitable for this role. Parameters, such as high hole mobility, zero nuclear spin and strong spin-orbit interaction, are fundamental for this application, and Ge posses all these characteristics. Within this thesis, in-plane Ge/Si core/shell nanowires (NWs) grown with selective area growth (SAG) technique via MOVPE were studied. Crucial is the need of epitaxial and defectsfree NWs, to minimise scattering and recombination sites. Several Ge core NWs grown at different growth parameters and fabrication method were compared using characterisation methods (principally SEM and TEM). NWs were then capped with a thin layer (nominally 5 nm) of Si, to protect the core and induce at the interface the type II band alignment. The Ge/Si interface and the cap crystal quality were investigated. At last, thought four-point measurements, some considerations regarding the NWs transport properties of both bare and capped NWs were discussed.