Self-organized hierarchical ZnS/SiO2 nanowire heterostructures

Novel hierarchical heterostructures formed by wrapping ZnS nanowires with highly dense SiO2 nanowires were successfully synthesized by a vapor-liquid-solid process. The as-synthesized products were characterized using X-ray diffraction, scanning electron microscopy and transmission electron microscopy equipped with an energy-dispersive X-ray spectrometer. Studies indicate that a typical hierarchical ZnS/SiO2 heterostructure consists of a single-crystalline ZnS nanowire (core) with diameter gradually decreasing from several hundred nanometers to 20 nm and adjacent amorphous SiO2 nanowires (branches) with diameters of about 20 nm. A possible growth mechanism was also proposed for the growth of the hierarchical heterostructures.