1 Introduction
2 Motivation
3 Outline of the Thesis
4 Band Structure Calculations
 4.1 The Cellular Method
 4.2 Variational Methods
 4.3 The k⋅p Method
 4.4 Perturbation Theory
 4.5 Effective Mass
 4.6 Spin-Orbit Interaction
  4.6.1 Spin
  4.6.2 Spin-Orbit Hamiltonian
  4.6.3 Spin Relaxation in Semiconductors
5 Effective k⋅p Hamiltonian
 5.1 Relaxed Silicon Structure
 5.2 Two-Band k⋅p Hamiltonian of [001] Valley at the X-Point Including Spin
 5.3 Analytical Wave Function Calculation
 5.4 Validation of the Analytical Solution
 5.5 Numerical Wave Functions Calculation
 5.6 Overlap Calculation
 5.7 Valley Splitting
6 Momentum Relaxation and Mobility Calculations
 6.1 Surface Roughness Limited Scattering Matrix Elements
 6.2 Surface Roughness Limited Momentum Relaxation Rates
 6.3 Phonon Induced Momentum Scattering Rates
 6.4 Momentum Relaxation Time Calculation
 6.5 Mobility Calculation
7 Spin Relaxation
 7.1 Strain Dependence of Surface Roughness Limited Spin Relaxation Matrix Elements
 7.2 Spin Relaxation Rate
  7.2.1 Surface Roughness Induced Spin Relaxation Rate
  7.2.2 Phonons
  7.2.3 Intravalley and g-Intervalley Relaxation Processes Rates
 7.3 Spin Lifetime Calculations
 7.4 Valley Splitting in Unstrained Films
 7.5 Primed Subbands and f-Processes
  7.5.1 Primed k⋅p Hamiltonian
  7.5.2 f-Process Relaxation Rate
 7.6 Results
8 Spin Field-Effect Transistor
 8.1 Spin Transport
 8.2 Effective Spin-Orbit Hamiltonian
  8.2.1 Spin-Orbit Interaction in the Semiconductor Channel
  8.2.2 D’yakonov-Perel’ Spin Relaxation
 8.3 Datta-Das SpinFET Model
 8.4 Code Parallelization
 8.5 Simulation Results
  8.5.1 InAs Channels
  8.5.2 Silicon Channels
9 Summary and Outlook