The influence of single-atomic-species and O-related defect termination on the electronic properties of Si nanocrystallites covered with a complete oxide shell were studied by means of density-functional theory and the local-density approximation. The oxide shell was analyzed in more detail to study the influence of O-related defects (O vacancy, double-bonded O, hydroxyl group) and single terminations (S, Cl, F) on the electronic and optical properties of the nanocrystallites. In contrast to the case of Si nanocrystallites passivated with H, the effect of these defects was drastically reduced in the presence of an oxide shell, leading to no defect level in the gap.Reduced Influence of Defects on Oxidized Si Nanocrystallites. L.E.Ramos, J.Furthmüller, F.Bechstedt: Physical Review B, 2005, 71[3], 035328 (7pp)