Nucleation and growth of Si nanocrystals in an amorphous SiO2 matrix

This paper discusses the physical mechanisms governing the nucleation and growth of Si nanocrystals embedded in an amorphous SiO2 matrix. Reactive pulsed laser deposition combined with a postannealing treatment is shown to be a flexible approach to synthesize Si nanocrystals. This technique ensures an excellent control of Si nanocrystal size by varying the oxygen pressure. By correlating nanocrystal size (measured by x-ray diffraction and transmission electron microscopy) with the nonoxidized Si volume fraction (determined by x-ray photoemission spectroscopy), it is found that the formation of nanocrystals follows classical nucleation theory, whereby the average distance between nuclei centers remains constant.