Si/ZnS and Si/ZnSe core/shell nanocrystal structures

We report on the synthesis of the Si/ZnS and Si/ZnSe core/shell nanocrystal structures produced via a two-stage thermal evaporation of SiO and ZnS or SiO and ZnSe powder mixtures. These core/shell structures display spherical and elliptical polycrystalline particles. Most of the Si/ZnS core/shell nanocrystal structures have diameters of similar to90-160 nm; the diameters of the cores and the thicknesses of the shells vary in a range of similar to50-100 nm. The diameters of the Si/ZnSe core/shell nanocrystal structures range from similar to150 to similar to200 nm; the thicknesses of the shells are rather uniform, similar to30 nm, and the diameters of the cores are thus in the range of similar to120-170 nm. Room-temperature photoluminescence was also investigated from as-synthesized Si/ZnS and Si/ZnSe core/shell nanocrystal structures, respectively. (C) 2004 American Institute of Physics.