Nino Leander Bartolo Ziino: Master thesis defence

Device Fabrication and Low Temperature Measurements of InAs Nanowires with Superconducting Al Shells

Abstract: This project is about the process of device fabrication based on InAs nanowires with superconducting Al shells. Two types of devices have been measured at low temperatures at which aluminum enters the superconducting phase. In the first case the resistance across the shell was measured in a four-probe measurement as a function of temperature and externally applied magnetic fields. For certain diameters and thicknesses of the shell, enhanced Little-Parks oscillations were observed, in which the critical temperature  Tc oscillates with periodicity of the flux quantum  Φ0 = h/2e. From these data the effective ratio between the cylinder diameter and coherence length could be estimated by a simplified model. In the second case, the conductivity across an exposed segment of the wire is measured as a function of applied bias and back-gate voltage as well as magnetic field.

Furthermore, a detailed description of the device fabrication is presented.