Ion-beam synthesis and structural characterization of ZnS nanocrystals in SiO2

In this letter, we report the ion-beam synthesis and the structural characterization of ZnS nanocrystals in SiO2. Both electron diffraction and x-ray diffraction measurements show the precipitation of ZnS nanocrystals having a wurtzite–2H structure and infrared spectroscopy confirms the presence of Zn–S bonding. Upon annealing, transmission electron microscopy observations show the Ostwald ripening of the precipitates coupled with a self-organization in two layers parallel to the free surface. This self-organization has been also detected by secondary ion mass spectroscopy, and its origin is discussed in terms of a pure Ostwald ripening process and/or a consequence of the implantation damage.