Scattering in Nanoscale Devices

In this thesis electronic transport through nanoscale devices is modeled by means of quantum physics. Moving from ballistic transport towards a detailed description of electron-phonon scattering, the used formalism changes from wave functions to the non-equilibrium Green’s functions (NEGF). The simulation framework consists of the quantum mechnical simulator SIMNAD, which was developed at the Integrated Systems Laboratory in two previous projects. SIMNAD was extended to a full self-consistent treatment of quantum wire based devices and incoherent transport. Within the wave function formulation, a new algorithm is presented including Büttiker scattering into the Scattering Matrix approach. The main extension is the implementation of a generic iterative solution procedure using NEGF, allowing the treatment of scattering in a perturbational way up to any order. The impact of electron-phonon scattering on the device characteristics is investigated together with new boundary conditions for the quantum transport equations. The mobility and the conductivity are studied as a function of the confinement and doping concentration. All simulations are performed within the effective mass approximation using the coupled mode expansion. The Coulomb interaction is approximated by the Hartree potential. The implementation of new boundary conditions for the Poisson equation enables simulations of nanoscale devices with metal-semiconductor contacts.