The results section is divided into two parts. First, chemical and crystallization processes observed during initial growth in the different conditions are described, as well as the resulting crystalline properties. Reflection High-Energy Electron Diffraction (RHEED) was used to monitor the crystallization process during growth. In order to investigate the chemistry after growth, in situ X-ray Photoelectron Spectroscopy (XPS) was used. X-ray Diffraction (XRD) and Atomic Force Microscopy (AFM) were used to relate the observed growth processes to respectively the crystalline properties and morphology of the films. Secondly, the contributions of the different sources of oxygen to those chemical and crystallization processes were investigated, as described above.