Charge and heat transport in semiconductor core-shell nanowires with temperature bias

Abstract

In this dissertation, we calculate the electronic charge and heat transport generated by a temperature gradient and a chemical potential bias in tubular semiconductor nanowires, in the presence of a magnetic field. We use the Landauer-Büttiker approach to calculate charge current, electronic heat current, Seebeck coefficient, thermal conductivity, and figure of merit. We also study the influence of the crosssection shape and shell thickness on the electronic conduction properties of tubular nanowires. Then, charge and heat transport in tubular nanowires for different polygonal cross-sections and different numbers of impurities with various strengths are studied. Effects of transverse geometry on the thermal conductivity of Si and Ge nanowires are investigated by using molecular dynamics simulations with the LAMMPS software. We consider nanowires with different polygonal cross-sections, tubular (hollow) nanowires, and core/shell nanowires with combinations of Si/Ge and Ge/Si. We also study the diffusion and phonon drag thermopower in Si nanowires through numerical calculations with tight-binding models and quantum transport.