Growth of novel ZnO nanohelices modified by SiO2-sheathed ZnO discs

Disc-modified nanohelices (DNHs) of ZnO were synthesized by thermal evaporation. The ZnO DNHs are constructed by nanowires which are regularly attached with discs. The axis of the DNH structure is along the ZnO[0001] direction. The pitch distance, the mean diameter, and the thickness of the nanowires are uniform for each ZnO DNH. Within one period there are 12 discs symmetrically attached on the surfaces of the nanowires. The discs are composed of nanometre-sized ZnO crystal cores and amorphous SiO 2 shells. The mechanism of formation of the nanostructures is also discussed.