Investigations of p-type quantum dots in GaSb nanowires

Sammanfattning: The purpose of this project is to investigate hole transport in p-type quantum dots formed in GaSb nanowire and operating as single hole transistors. The individual and controlled hole-spin confinement in such system yields a variety of proposed applications for spintronics or quantum computation. In contrast to more conventional n-type material system, however, p-type quantum devices benefit from reduced hyperfine interaction, which are anticipated to result in longer spin lifetimes. One such p-type material system is GaSb, which to date has not been investigated in detail. This project starts with sample fabrication of p-type quantum dots in GaSb nanowires by the deposition of quantum dot island with Schottky contacts of nanowire segments combined with underlying metallic gate stripes. Transport characterization of the device properties are performed at low temperature. The single quantum dot behaviour in different hole occupancy states is investigated by controlling the gate stripe potentials and the multi-quantum dot formation is also observed as well. Finally, via magneto-transport spectroscopy, the Zeeman effect is studied and g-factors of different orbital states are extracted with the measurement of spin-orbit interaction energy to be Eso = 113 µeV.