Cover; Half Title; Title Page; Copyright Page; Dedication; Contents; Preface; 1 Silicon Nanocrystals Enabling Silicon Photonics ; 1.1 The Need of Silicon Photonics ; 1.1.1 Waveguides. 1.1.2 Modulators 1.1.3 Sources ; 1.1.4 Detectors ; 1.2 Nanosilicon for Photonics ; 1.2.1 Si-nc Waveguides. 1.2.2 Nonlinear Effects: Fast Optical Switches 1.2.3 Light Emission and Optical Gain in Si Nanocrystals ; 1.2.4 Si Nanocrystals LEDs. 1.2.5 Er Coupled to Nano-Si for Optical Amplifiers 1.2.6 Carrier Absorption within Si Nanocrystals Waveguides ; 1.3 Conclusions. 2 Silicon Nanocrystals for Photonics and Photovoltaics: Ab initio Results 2.1 Introduction ; 2.2 Silicon Nanocrystals Embedded in Matrices.